Avoid the error CURAND failure 201

You are probably running on a Pascal GPU (for example a GTX 1080) with CUDA 7.5. You need to upgrade to CUDA 8.0. Also you cannot use any of the provided CNTK binaries. All versions up to and including 1.7 are linked against CUDA 7.5 and will not work with Pascal GPUs.

TODO: list some helpful steps for people to transition from 7.5 to 8