Fixed a bug where hg command processing was crashing on Windows servers

This was due to using os.linesep, however the resulting message we get is actually from a linux machine and therefore on Windows using \r\n would result in none of them being found.
Added ability to select buildslave on force build

Moved the force build form into a new forms.py file to redduce the load that is uses on the server
Fixed a bug in select slave where builds would wait forever

- Tidied up the way we are detecting if a build should be the "same" when selected slaves are involved
Cleared up a bit of code after a review from maria
Fixed minor bug in the queue where it shows more compatible slaves than there are when running on a specified agent
Merge branch 'staging' into specifySlave

Conflicts:
	master/buildbot/status/web/files/prod/script/project/popup.js