It's no longer retarded. All object interdependencies are stored as OIDs
instead of actual objects. This should be hundreds of times faster,
specially on big repositories. Heck, who knows, maye it doesn't even
segfault -- wouldn't that be awesome?

What has changed on the API?

	`git_commit_parent`, `git_commit_tree`, `git_tag_target` now return
	their values through a pointer-to-pointer, and have an error code.

	`git_commit_set_tree` and `git_tag_set_target` now return an error
	code and may fail.

	`git_repository_free__no_gc` has been deprecated because it's
	stupid. Since there are no longer any interdependencies between
	objects, we don't need internal reference counting, and GC
	never fails or double-free's pointers.

	`git_object_close` now does a very sane thing: marks an object
	as unused. Closed objects will be eventually free'd from the
	object cache based on LRU. Please use `git_object_close` from
	the garbage collector `destroy` method on your bindings. It's
	100% safe.

	`git_repository_gc` is a new method that forces a garbage collector
	pass through the repo, to free as many LRU objects as possible.
	This is useful if we are running out of memory.