Make project title link to project homepage

Implements feature request: http://feedback.gitlab.com/forums/176466-general/suggestions/5491715-please-small-fix-click-on-title-of-repo-to-go-to

Make project title link to project homepage. Minor edit that does not appear to negatively affect [any pages used on](https://github.com/gitlabhq/gitlabhq/search?utf8=%E2%9C%93&q=project_title&type=Code).
@bbodenmiller I think no. As I remember we had project validation even before namespaces were created