this adds recognition of the git_protocol setting when:
- creating a repo
- cloning a repo
- forking a repo
- forking/pushing during pr create
- checking out a PR
additionally, it:
- consolidates remote adding to use AddRemote; this introduces a fetch
where there previously hadn't been one
- changes repo clone to accept an ssh url
- changes repo fork to accept an ssh url
i just added basic unit tests; adding new test cases for all of the
above scenarios seemed like diminishing returns.
The 2nd argument now unused since we've determined that, in practice, we
can safely fetch git objects from a freshly created fork on GitHub and
that we don't need the remote URL-swapping workaround.
