1. Replace params key 'q' with 'extended_sha1'. A extended SHA1 syntax is explained in 'man gitrevisions'.
2. Change the placeholder of looking for commit.
3. Change the label of ref filter.

@Options enable to keep params when switching ref.

Also specify separate project factory for project with filled repo

It uses params[:id] instead of request.fullpath.
It should fix #3132.

Files and Commits render a 404 when running with relative_url_root.

Let's assume your path is = "project/tree/master/This%20Is%20valid"
In this case gitlab renders a 404.

To fix this we should decode the path so that it looks like
"project/tree/master/This Is valid"

Update docs a bit