ci-status with remote repository specification with -r option

When local repository's remotes are like:

* michiels https://github.com/michiels/pencilbox.git
* mine https://github.com/__username__/pencilbox.git

Then run `ci-status` fetches always from 'michiels' remote's build status.
Because there are no 'upstream', 'github' or 'origin' remote names.
So, based on dictionary order, 'michiels' remote is choosed as a main
remote repository and there is no way to fetch 'mine' remote ci-status.

This commit make it possible to choose remote repository's commit
build status with -r option like:

    hub ci-status -r mine __commit_sha__

You can also use -v option to retrieve build url:

    hub ci-status -r mine __commit_sha__ -v