Streamlining branches

[desilinguist]

@dmnapolitano @slava92 @tamarl08 I just renamed the stable_0.2.2 branch to stable_0.2.3 since the version number was actually 0.2.3 there. Here's what else I am thinking:

1. We should just rename master to stable leave develop as is.
2. Once we internally upgrade our ETS applications to use the latest match, we should delete stable_0.2.3.

From then on, just like RSMTool, stable will always point to the last released version and develop will accumulate changes until the next release.

Thoughts?