TypeError on Mac OS X 10.10 using python 2.7
I've tried

Mac OS X 10.10.2 (Yosemite)

```
Traceback (most recent call last):
  File "/usr/local/bin/icon-font-to-png", line 8, in <module>
    from icon_font_to_png import command_line
  File "/Library/Python/2.7/site-packages/icon_font_to_png/__init__.py", line 2, in <module>
    from .icon_font_downloader import (
  File "/Library/Python/2.7/site-packages/icon_font_to_png/icon_font_downloader.py", line 15, in <module>
    class IconFontDownloader(object, with_metaclass(ABCMeta)):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/abc.py", line 87, in __new__
    cls = super(ABCMeta, mcls).__new__(mcls, name, bases, namespace)
TypeError: Error when calling the metaclass bases
    Cannot create a consistent method resolution
order (MRO) for bases NewBase, object
```

The following is the output of installing icon-font-to-png (and dependencies) using pip:

```
Downloading/unpacking icon-font-to-png
  Downloading icon_font_to_png-0.3.2-py2.py3-none-any.whl
Downloading/unpacking tinycss>=0.3 (from icon-font-to-png)
  Downloading tinycss-0.3.tar.gz (72kB): 72kB downloaded
  Running setup.py (path:/private/tmp/pip_build_root/tinycss/setup.py) egg_info for package tinycss
    Building without Cython.

    no previously-included directories found matching 'docs/_build'
Downloading/unpacking requests>=2.9.1 (from icon-font-to-png)
  Downloading requests-2.9.1-py2.py3-none-any.whl (501kB): 501kB downloaded
Downloading/unpacking pillow>=3.0.0 (from icon-font-to-png)
  Downloading Pillow-3.1.1-cp27-none-macosx_10_6_intel.macosx_10_9_intel.macosx_10_9_x86_64.macosx_10_10_intel.macosx_10_10_x86_64.whl (2.9MB): 2.9MB downloaded
Downloading/unpacking six>=1.10.0 (from icon-font-to-png)
  Downloading six-1.10.0-py2.py3-none-any.whl
Installing collected packages: icon-font-to-png, tinycss, requests, pillow, six
  Running setup.py install for tinycss
    Building without Cython.
    building 'tinycss.speedups' extension
    cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c tinycss/speedups.c -o build/temp.macosx-10.10-intel-2.7/tinycss/speedups.o
    tinycss/speedups.c:705:14: warning: explicitly assigning value of variable of type 'PyObject *' (aka 'struct _object *') to itself [-Wself-assign]
      __pyx_self = __pyx_self;
      ~~~~~~~~~~ ^ ~~~~~~~~~~
    tinycss/speedups.c:1571:14: warning: explicitly assigning value of variable of type 'PyObject *' (aka 'struct _object *') to itself [-Wself-assign]
      __pyx_self = __pyx_self;
      ~~~~~~~~~~ ^ ~~~~~~~~~~
    tinycss/speedups.c:5348:33: warning: unused function '__Pyx_PyInt_FromSize_t' [-Wunused-function]
    static CYTHON_INLINE PyObject * __Pyx_PyInt_FromSize_t(size_t ival) {
                                    ^
    tinycss/speedups.c:5362:29: warning: unused function '__Pyx_PyInt_AsSize_t' [-Wunused-function]
    static CYTHON_INLINE size_t __Pyx_PyInt_AsSize_t(PyObject* x) {
                                ^
    tinycss/speedups.c:469:32: warning: unused function '__Pyx_GetItemInt_Tuple_Fast' [-Wunused-function]
    static CYTHON_INLINE PyObject *__Pyx_GetItemInt_Tuple_Fast(PyObject *o, Py_ssize_t i) {
                                   ^
    tinycss/speedups.c:509:26: warning: unused function '__Pyx_NegateNonNeg' [-Wunused-function]
    static CYTHON_INLINE int __Pyx_NegateNonNeg(int b) {
                             ^
    tinycss/speedups.c:512:32: warning: unused function '__Pyx_PyBoolOrNull_FromLong' [-Wunused-function]
    static CYTHON_INLINE PyObject* __Pyx_PyBoolOrNull_FromLong(long b) {
                                   ^
    tinycss/speedups.c:4481:36: warning: unused function '__Pyx_PyInt_AsUnsignedChar' [-Wunused-function]
    static CYTHON_INLINE unsigned char __Pyx_PyInt_AsUnsignedChar(PyObject* x) {
                                       ^
    tinycss/speedups.c:4500:37: warning: unused function '__Pyx_PyInt_AsUnsignedShort' [-Wunused-function]
    static CYTHON_INLINE unsigned short __Pyx_PyInt_AsUnsignedShort(PyObject* x) {
                                        ^
    tinycss/speedups.c:4519:35: warning: unused function '__Pyx_PyInt_AsUnsignedInt' [-Wunused-function]
    static CYTHON_INLINE unsigned int __Pyx_PyInt_AsUnsignedInt(PyObject* x) {
                                      ^
    tinycss/speedups.c:4538:27: warning: unused function '__Pyx_PyInt_AsChar' [-Wunused-function]
    static CYTHON_INLINE char __Pyx_PyInt_AsChar(PyObject* x) {
                              ^
    tinycss/speedups.c:4557:28: warning: unused function '__Pyx_PyInt_AsShort' [-Wunused-function]
    static CYTHON_INLINE short __Pyx_PyInt_AsShort(PyObject* x) {
                               ^
    tinycss/speedups.c:4595:34: warning: unused function '__Pyx_PyInt_AsSignedChar' [-Wunused-function]
    static CYTHON_INLINE signed char __Pyx_PyInt_AsSignedChar(PyObject* x) {
                                     ^
    tinycss/speedups.c:4614:35: warning: unused function '__Pyx_PyInt_AsSignedShort' [-Wunused-function]
    static CYTHON_INLINE signed short __Pyx_PyInt_AsSignedShort(PyObject* x) {
                                      ^
    tinycss/speedups.c:4633:33: warning: unused function '__Pyx_PyInt_AsSignedInt' [-Wunused-function]
    static CYTHON_INLINE signed int __Pyx_PyInt_AsSignedInt(PyObject* x) {
                                    ^
    tinycss/speedups.c:4652:26: warning: unused function '__Pyx_PyInt_AsLongDouble' [-Wunused-function]
    static CYTHON_INLINE int __Pyx_PyInt_AsLongDouble(PyObject* x) {
                             ^
    tinycss/speedups.c:4776:35: warning: function '__Pyx_PyInt_AsLongLong' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    static CYTHON_INLINE PY_LONG_LONG __Pyx_PyInt_AsLongLong(PyObject* x) {
                                      ^
    tinycss/speedups.c:4846:42: warning: function '__Pyx_PyInt_AsSignedLongLong' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    static CYTHON_INLINE signed PY_LONG_LONG __Pyx_PyInt_AsSignedLongLong(PyObject* x) {
                                             ^
    tinycss/speedups.c:4896:27: warning: unused function '__Pyx_ErrFetch' [-Wunused-function]
    static CYTHON_INLINE void __Pyx_ErrFetch(PyObject **type, PyObject **value, PyObject **tb) {
                              ^
    19 warnings generated.
    tinycss/speedups.c:705:14: warning: explicitly assigning value of variable of type 'PyObject *' (aka 'struct _object *') to itself [-Wself-assign]
      __pyx_self = __pyx_self;
      ~~~~~~~~~~ ^ ~~~~~~~~~~
    tinycss/speedups.c:1571:14: warning: explicitly assigning value of variable of type 'PyObject *' (aka 'struct _object *') to itself [-Wself-assign]
      __pyx_self = __pyx_self;
      ~~~~~~~~~~ ^ ~~~~~~~~~~
    tinycss/speedups.c:5348:33: warning: unused function '__Pyx_PyInt_FromSize_t' [-Wunused-function]
    static CYTHON_INLINE PyObject * __Pyx_PyInt_FromSize_t(size_t ival) {
                                    ^
    tinycss/speedups.c:5362:29: warning: unused function '__Pyx_PyInt_AsSize_t' [-Wunused-function]
    static CYTHON_INLINE size_t __Pyx_PyInt_AsSize_t(PyObject* x) {
                                ^
    tinycss/speedups.c:469:32: warning: unused function '__Pyx_GetItemInt_Tuple_Fast' [-Wunused-function]
    static CYTHON_INLINE PyObject *__Pyx_GetItemInt_Tuple_Fast(PyObject *o, Py_ssize_t i) {
                                   ^
    tinycss/speedups.c:509:26: warning: unused function '__Pyx_NegateNonNeg' [-Wunused-function]
    static CYTHON_INLINE int __Pyx_NegateNonNeg(int b) {
                             ^
    tinycss/speedups.c:512:32: warning: unused function '__Pyx_PyBoolOrNull_FromLong' [-Wunused-function]
    static CYTHON_INLINE PyObject* __Pyx_PyBoolOrNull_FromLong(long b) {
                                   ^
    tinycss/speedups.c:4481:36: warning: unused function '__Pyx_PyInt_AsUnsignedChar' [-Wunused-function]
    static CYTHON_INLINE unsigned char __Pyx_PyInt_AsUnsignedChar(PyObject* x) {
                                       ^
    tinycss/speedups.c:4500:37: warning: unused function '__Pyx_PyInt_AsUnsignedShort' [-Wunused-function]
    static CYTHON_INLINE unsigned short __Pyx_PyInt_AsUnsignedShort(PyObject* x) {
                                        ^
    tinycss/speedups.c:4519:35: warning: unused function '__Pyx_PyInt_AsUnsignedInt' [-Wunused-function]
    static CYTHON_INLINE unsigned int __Pyx_PyInt_AsUnsignedInt(PyObject* x) {
                                      ^
    tinycss/speedups.c:4538:27: warning: unused function '__Pyx_PyInt_AsChar' [-Wunused-function]
    static CYTHON_INLINE char __Pyx_PyInt_AsChar(PyObject* x) {
                              ^
    tinycss/speedups.c:4557:28: warning: unused function '__Pyx_PyInt_AsShort' [-Wunused-function]
    static CYTHON_INLINE short __Pyx_PyInt_AsShort(PyObject* x) {
                               ^
    tinycss/speedups.c:4595:34: warning: unused function '__Pyx_PyInt_AsSignedChar' [-Wunused-function]
    static CYTHON_INLINE signed char __Pyx_PyInt_AsSignedChar(PyObject* x) {
                                     ^
    tinycss/speedups.c:4614:35: warning: unused function '__Pyx_PyInt_AsSignedShort' [-Wunused-function]
    static CYTHON_INLINE signed short __Pyx_PyInt_AsSignedShort(PyObject* x) {
                                      ^
    tinycss/speedups.c:4633:33: warning: unused function '__Pyx_PyInt_AsSignedInt' [-Wunused-function]
    static CYTHON_INLINE signed int __Pyx_PyInt_AsSignedInt(PyObject* x) {
                                    ^
    tinycss/speedups.c:4652:26: warning: unused function '__Pyx_PyInt_AsLongDouble' [-Wunused-function]
    static CYTHON_INLINE int __Pyx_PyInt_AsLongDouble(PyObject* x) {
                             ^
    tinycss/speedups.c:4776:35: warning: function '__Pyx_PyInt_AsLongLong' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    static CYTHON_INLINE PY_LONG_LONG __Pyx_PyInt_AsLongLong(PyObject* x) {
                                      ^
    tinycss/speedups.c:4846:42: warning: function '__Pyx_PyInt_AsSignedLongLong' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    static CYTHON_INLINE signed PY_LONG_LONG __Pyx_PyInt_AsSignedLongLong(PyObject* x) {
                                             ^
    tinycss/speedups.c:4896:27: warning: unused function '__Pyx_ErrFetch' [-Wunused-function]
    static CYTHON_INLINE void __Pyx_ErrFetch(PyObject **type, PyObject **value, PyObject **tb) {
                              ^
    19 warnings generated.
    cc -bundle -undefined dynamic_lookup -arch x86_64 -arch i386 -Wl,-F. build/temp.macosx-10.10-intel-2.7/tinycss/speedups.o -o build/lib.macosx-10.10-intel-2.7/tinycss/speedups.so

    no previously-included directories found matching 'docs/_build'
Successfully installed icon-font-to-png tinycss requests pillow six
Cleaning up...
```

I've been able to successfully install and run `icon-font-to-png` on a linux machine however and it appears the issue might be related to the install of `pillow`. I'm not too familiar with `pip` and I might be posting this in the wrong repository, if so, please let me know!
