Add new convenience options like `--no-branches`, `--stash`, etc.

All of the following can be accomplished using reference filtering (#75), but we could add new options to make them a tad more convenient (and these options would nicely complement `--branches`, `--tags`, and `--remotes`):

* `--no-branches` — equivalent to `--exclude=refs/heads`
* `--no-tags` — equivalent to `--exclude=refs/tags`
* `--no-remotes` — equivalent to `--exclude=refs/remotes`
* `--notes` / `--no-notes` — equivalent to `--include=refs/notes` / `--exclude=refs/notes`
* `--stash` / `--no-stash` — equivalent to `--include=refs/stash` / `--exclude=refs/stash`