Fixed an issue when stop() was raising an exception incorrectly if timeout for buildstep was None (this for example stopped log watcher from correctly closing file handles) because self.timer was re-used for entirely different purpose but stop() code was unaware of such use
* Renamed some timers to be more understandable
* Added a note in 0.8.8 release notes about the fix
Merge branch 'slave_timer_fix' of git://github.com/JustAMan/buildbot