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>
Report errors for all builder at once.

This also changes all of the config error reporting to use `config.error`
instead of sometimes using `.addError`.
Merge pull request #609 from tomprince/builder-errors

Report errors for all builder at once.
Fix a couple of errors introduced by using config.error everywhere.
Lock management: store LockAccess instances in class instances

Moves some common code of converting between Lock and LockAccess to a common
place.
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