[src,egs,scripts]: improve use of sum-to-one penalty in combination, provide script support; examples of use of dropout in TDNN+LSTMs; change minibatch-size in combination phase.

Conflicts:
	egs/wsj/s5/steps/libs/nnet3/xconfig/lstm.py

Conflicts:
	src/nnet3/nnet-chain-combine.cc
	src/nnet3/nnet-combine.cc

The scripts used a hard-coded path including '_sp' suffix irrespective of whether speed_perturb is set.

Conflicts:
	egs/wsj/s5/steps/libs/nnet3/train/chain_objf/acoustic_model.py
	egs/wsj/s5/steps/libs/nnet3/train/frame_level_objf/common.py
	egs/wsj/s5/steps/nnet3/report/generate_plots.py
	egs/wsj/s5/steps/nnet3/train_dnn.py
	egs/wsj/s5/steps/nnet3/train_raw_dnn.py
	src/nnet3/nnet-combine.cc
	tools/extras/openfstwin-1.3.4.patch

[src][egs] Various script updates/clarifications, remove no-op options; remove now-removed options from some discriminative-training egs scripts; various bug fixes/tuning.