Move all hg server related codes into projector
There are currently client-side memory leaks while trying to pull from repo with extra heads. Turning off messages signal/listener is a workaround pushed recently.
We need to move codes from vcs.web.simplevcs into projector itself or create another small project with Django <-> SCM proxying. Projector would be less "loose coupled" but fixing problems would be a little bit more easier for one developer.