Full URL handling in patterns.

Here is a draft (but working) patch that allows sections to match against the full path.
Very usefull if you want different themes on different urls or subdomains.

http://*.example.com/* as "path" will show a theme on http://foo.example.com/bax or http://bar.example.com/bay etc
http://foo.example.com/user/* will activate a theme only on foo.example.com path user. etc.

If this idea is found nice, we still need to update the help and description texts a little and might want to check if there are performance issues related with this.