First pass at enabling fetches.
Add initializers for GTRemote.
Allow getting a branch's remote directly.
Setup the credential callback.
Update libgit2 to libgit2/libgit2@85e1eded6a5302b25c339988a6828aa45fbc23d8

which is waiting for merging in libgit2/libgit2#1729
Fix enum value that disappeared.
API to get a remote's repository back.
Make that call block-based.
Add some missing accessors.
Review.
Cleanup our callbacks.
Synchronize accesses on self.
Merge branch 'master' into fetch
Fix error reporting.
Add `BOOL *stop` parameters.
Remove `-cancelOperation`.
Add `-pushURLString` accessor.
Disconnect the remote after fetch.
Merge branch 'master' into fetch
Remote renaming.