trunk,nnet1: adding check that CUDA compiled-in in NN training scripts,
- utils/nnet/make_nnet_proto.py : adding comments



git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@4565 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8
trunk: modification to how ApplyFloor works to avoid failure in SymPosDefEig (it's no longer necessary as Eig is now sufficiently stable).

git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@4566 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8