Add testing cost.

add batch reader into reader design doc

Training the understand sentiment model with the new API.

Fix k8s cluster job rerunable

semantic_role_labeling v2 api

remove osx build from CI

We don't officially support OSX.
And Travis CI takes a lot of time to build osx. (long time in pending state.
Probably because travis ci don't have enough osx machines.

Fix duplicated forward/backward in trainer.

Check system's protobuf for internal users

support rnn

CONLL05 dataset for SRL

Add vgg training via api v2

Fix unittest