feat(repo-tools): show status image popup to everyone

If you can see the repository, then you should also be able to see the
status of said repository (and status image), so you should also be able
to copy the link to a status image.

Close travis-ci/travis-ci#1881.
Merge pull request #253 from travis-ci/hh-show-status-image-popup-everyone

feat(repo-tools): show status image popup to everyone