Add ability to pause build-slaves.

Signed-off-by: Tom Prince <tom.prince@ualberta.net>
Start implementing option to pause a slave.

Signed-off-by: Tom Prince <tom.prince@ualberta.net>
Refactor code for clobberOnFailure. Don't clobber() for this case, use independent functions
Don't allow git source step to make shallow in any mode other than clobber

Fixes #2154
- New WIP for Clean shutdown.
Also decode the filed names when force-building.

With ForceScheduler, it is possible to have semi-arbitrary names. This
also cleans up the arg-preprocessing code somewhat.

Refs #1054.
Allow forcing on multiple builders at once.

The web status currently does this by forcing multiple times, once for each builder,
creating a separate buildset for each. Instead, teach ForceScheduler to support
starting multiple builders in a single buildset, and refactor the webstatus code to
support that.

Fixes #2342.
Git: Don't break when there is a file called `FETCH_HEAD`.

We want to refer to the branch FETCH_HEAD, not a file, so let git know that.
(Reported by loul2 on #buildbot)
GitPoller: Disambiguate versions from file names.

The revision that we use for GitPoller are probably never going to exists
as files, but it doesn't cost us anything to avoid issues here.
Add getRecentBuildsets to buildsets db connector

Change-Id: I8d48afcb65b165374d9bc47fae048ef4f374ff37
Update pyflakes project url.  divmod.org says it's offline, and to use launchpad instead.
Add support for builder descriptions
Implement requested change to from a <pre> to a <div> for builder descriptions, fix tests broken by addition of builder descriptions.
Adding docs for builder descriptions.
Fix bug with builder descriptions not being updated on reconfig.
Add getDescription to IBuildStatus
test_process_builder: Factor out some common code.
Add a tests for builder reconfig.
fix pyflakes
Fix BuildStatus.getAllGotRevisions to properly handle vcs that use int.

Fixes #2388, #2380.