Better debugging of remote configuration keys
Add --shallow functionality

This function, added to all instances or subclasses of GitRepoCommand,
allows the user to stop scc from recursively resolving and operating on
the submodules of the current repository.  This is particularly
important when an integration branch is not present on all submodules or
where scc operations on one or more submodules is undesirable.
Expand --remote to all GitRepoCommand's (See #57)
Refactor to use git_config
Merge pull request #88 from chris-allan/shallow-and-remotes

Shallow and remotes