Use a variable rather than constructor argument for allow_shutdown.

This is consistent with the other options, and makes it easy to see all
the settings.
Report config errors, rather than assertions in IRCClient.
Fix whitespace.
Remove no-op addFactoryArguments calls.

addFactoryArguments is deprecated now.
s/validate_master_option/validateMasterOption/
Update docs referring to the old getProjectName()

The buildbot.status.master.getProjectName() has been renamed to
getTitle().
convert calls to addStep in factory.py to use instances
Merge remote-tracking branch 'origin/buildbot-0.8.8' into buildbot-0.8.8
relnotes for bug 2502
Merge branch 'buildbot-0.8.8'
Merge branch 'buildbot-0.8.8'