trunk,nnet1: mostly cosmetic changes
- nnet-loss.cc - simplicfications of old code
- lattice-to-ctm-conf.cc - print average confidence per-sentence,
- steps/nnet/train.sh - use /tmp for local caching of features, or override by copy_feats_rootdir,



git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@4528 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8