Always getting X instead of an icon
Hi! I've got an issue with the library... 
No matter how I use it (either with `IconicsImageView` or with `IconicsDrawable` with a regular `ImageView`), no matter which icon I wanna display (from which set) I always get an image of an X within a rectangle. 

This particular example was achieved with:

```
<com.mikepenz.iconics.view.IconicsImageView
    android:layout_width="72dp"
    android:layout_height="72dp"
    app:iiv_color="@android:color/holo_red_dark"
    app:iiv_icon="gmd-favorite"/>
```

![](https://cloud.githubusercontent.com/assets/6371716/12577980/53ca6bf2-c41e-11e5-952f-503d4675841e.png)

My dependencies include:

```
compile 'com.mikepenz:iconics-core:2.5.5@aar'
compile 'com.mikepenz:google-material-typeface:2.1.0.1.original@aar'
```

It's a Nexus 5 with Android 6.0.1

Any idea what might be the issue?
