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>
- New WIP for Clean shutdown.
Raise ImportError instead of exiting, if buildbot.test can't be imported.

This apparently causes issue with 'pydoc -k', and is in general not nice.
Trial still fails with a sensible error message.

This is a slave-side reflection of commit 126e02341c76bd5a027c2ca5a8467aa5708228f2
initial master side P4() source step
removed defaultBranch argument which has no purpose. Improved API docs. Added P4:.. prefixing on logging.
added docs for P4 master side source step
don't run sqlalchemy betas, either
Add white-space: pre-wrap to the default CSS.

Make preformatted text wrap by default, so that you don't have to scroll
countless furlongs horizontally or copy and paste into a local text
editor in order to read long log output.

Pre-wrap appears to be supported in all modern browsers. "word-wrap:
break-word" could be added if support for IE <= 7 is desired.
Add a note about default.css wrapping preformatted text.
Add VC11 step
Merge pull request #599 from geraldcombs/master

Make preformatted text wrap by default
Update documentation to include VS2012 and add a test for it
Fix typo
address jaredgrubb's pull feedback
Merge branch 'master' of git://github.com/caen1/buildbot
Add support for trial -j option

trial -j/--jobs is only supported in Twisted>=12.3.0
Move jobs setup to start method so that trialJobs can be Renderable
Add documentation and fix failing assertion
Rename trialJobs to jobs