This wasn't used anyway. A good idea would be to create a new
branchcontroller that takes care of all these revs, rather than
letting PBGitRepository take care of that
That's why it's there, after all. This also makes the system
more robust and catches some more errors.
The next thing this enables is to also allow right-clicking
on refs in the commit list.
The ref functionality is somewhat weird right now, in that
some parts of the code require a nil array when there are no
refs. So, we add a good removeRef accessor to keep track of this
Mark Bestley