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).
Do we really need `simple_sanitize` here? I'm really not sure, but if yes, then it might mean we are vulnerable elsewhere since there are many project.name used throughout the app without it. If it really is necessary, sanitation should happen before entering the DB to fix all those problems.