As fork is not working at the moment with Hg support we need to remove
all references of fork from the UI.
This patch removes references to the fork button, list of forks and a few other things of similar use.
note : I also moved https://heptapod.octobus.net/heptapod/heptapod/commit/f332cf51c337353d9e9442d423abb832c5fd50d0 out of the history in the branch when I tried to rewrite the history properly, I guess we can merge it in heptapod branch with another merge request and it won't appear in this one anymore ? @madprog