check whether staged changes exist before committing
Merge pull request #20 from JamesLavin/update-git-only-if-changed

check whether staged changes exist before committing
attempt to push submodule changes back only if submodules actually changed
Merge pull request #21 from JamesLavin/push-git-changes-back-only-if-submodules-changed

attempt to push submodule changes back only if submodules actually chang...