trunk: online-nnet2 decoding setup: adding scripts which make it possible to...

trunk: online-nnet2 decoding setup: adding scripts which make it possible to estimate the iVectors per speaker, excluding silence (so not-truly-online decoding).  Some code changes for iVector which allow for scaling up the prior term when the data count exceeds a certain value (this seems to be important, for some reason).  And misc. code fixes.

git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@4865 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8