Created by: reyoung

Under developing. Trying to expose ParameterUpdater APIs.

@jacquesqiao but to make read trainer_config.py to one file can be under developing now.

You can get my feature branch by

git remote add yy_remote https://github.com/reyoung/Paddle.git
git fetch yy_remote feature/mnist_train_api
git checkout FETCH_HEAD
git checkout -b YOUR_LOCAL_BRANCH_NAME

and push your commits into your repo. Thx.