Keras 2 and keras-contrib pull request process (#5800)
Keras 2 and keras-contrib pull request process (#5800)

* Keras 2 and keras-contrib pull request process

Explains the new pull request procedures for Keras 1, Keras 2, and keras-contrib, should resolve https://github.com/fchollet/keras/issues/5270.
Based on discussion in https://github.com/fchollet/keras/issues/4944 and https://github.com/farizrahman4u/keras-contrib/issues/9.

* CONTRIBUTING.md keras-2 release update

keras-team/keras,keras-team/keras