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>
Add some better error handling to 'buildbot try'.

Refs #2392.
Remove potentially misleading message about rebuilding builds.

It isn't possible to reliably detect when a build can be rebuilt exactly,
so don't try.

Fixes #2377.
Wrap looping calls in try-except blocks.

LoopingCall cancels anything after it raises an exception,
so catch them before they reach it.

Refs #1038.
Make contributed pollers use PollingChangeSource.

Refs #1038.
svnpoller: Don't fail when revisions contain changes outside our prefix.

When getting the logs, revisions that don't affect the SVNPoller.svnurl path
are already being filtered out by svn.  Since the poller doesn't even consider
them, I would expect it not to consider unrelated paths that come with the logs
and just filter them out.

Fixes #385.
svnpoller: Replace an assert with a real test.
Merge remote-tracking branch 'origin' into poc/pause

Conflicts:
	master/buildbot/status/web/authz.py
	master/buildbot/status/web/slaves.py
	master/docs/cfg-statustargets.texinfo
Make sure to start builds, when unpausing a slave.
Add some sanity checks to BuildStep.__init__.

Fixes #2271.
Remove stdlib logging from buildbot.schedulers.base.
Typo.
Don't require pycrpyto for telnet manhole.

Fixes #2160.
Merge branch 'LockAccessPatch' of git://github.com/jaredgrubb/buildbot
fix minor pyflakes
Merge branch 'pull617'
fix docs
Merge pull request #618 from tomprince/bug2392

Add some better error handling to 'buildbot try'.
Merge pull request #619 from tomprince/bug2377

Remove potentially misleading message about rebuilding builds.