Compiling on Ubuntu 14.04
Addition flags are required when compiling on
```
Ubuntu 14.04 64-bit
CMake version 3.2.2
CUDA V8.0.61
GCC 5.5.0
libuv 1.19.2
```
Add `-std=c++11` to `CUDA_NVCC_FLAGS` in [CUDA.cmake](https://github.com/xmrig/xmrig-nvidia/blob/master/cmake/CUDA.cmake#L97) and `set(LIBS "-ldl")` in [flags.cmake](https://github.com/xmrig/xmrig-nvidia/blob/master/cmake/flags.cmake#L20)
