trunk: Change to keyword search (e.g. as used in BABEL program) to be more...

trunk: Change to keyword search (e.g. as used in BABEL program) to be more exact, e.g. with regard to time boundaries; make wspecifiers to scp support permissive (,p) option (see changes to docs for explanation); modify lattice-to-nbest to support random generation from lattice; add some nnet code for perturbing egs (no scripts to demonstrate this yet); misc cosmetic changes.

git-svn-id: https://svn.code.sf.net/p/kaldi/code/trunk@3424 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8