Add a "stable" branch

[johnezang]

Get around to adding a stable branch that can be the formal recommend branch for people that want to include JSONKit via a git submodule. The purpose would be to track "production quality and stable" changes to JSONKit inbetween version milestones.

The changes that would land in stable would be conservative, and people should always feel confident in syncing their local stable branch following versions of JSONKit with the latest commits to the stable branch in the github.com repository.

It might make some sense to create stable branches of different versions. This would allow people to "freeze" their projects JSONKit git submodule to a particular version, but still pick up important / critical fixes to that particular version without having to worry about whether changes required to implement new features for later versions interacting in unexpected ways with their app.

Comments from the community are welcome.

[djbe]

This might be a good starting point: http://nvie.com/posts/a-successful-git-branching-model/