Fork v5
This is an updated version of the previously rejected pull request: .
- "Fork" button on project page will create new project in user's namespace
- updated to use GitLab v5 rather than 4.2, including using gitlab-shell rather than gitolite
- improved test coverage
- addition of table forked_project_links to track which projects are forked from where
- this will be important to enhance merge requests to go across forked repos