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)
merge master -D org -I include -E exclude: PR 82 (Add logic to create tag while updating submodules)
merge master -D org -I include -E exclude: PR 87 (Refactor the TestRebase integration test)
merge master -D org -I include -E exclude: PR 88 (Shallow and remotes)