Add PBGitStash and PBStashController (minus PBCommand stuff)
Clean up PBStashController.
Remove menu from PBStashController.
Fix waring about missing -path method.
Load stash controller from PBGitRepository.
Add stashes to sidebar.
Add stash icon.
Remove unconnected outlets and now unused or do-nothing code that references them.
Remove observer for stashes and submodules.
Remove unneeded forward declaration.
Use constants for observing contexts.
Change observing context pointer to void * and use direct pointer comparison.
Refactor. Own methods to handle change notifications.
Move resources to own folder.