Clean patch for master_sync
Respond to review notes.
clean up code
Add two-state back to ControlLogpotmeterBehaviorback. For some reason I believed this was unused but the volume sliders use it.
Wait for the EngineWorkerScheduler thread to complete before destruction. This fixes a crash-on-exit that I believe is caused since we no longer have a SyncWorker.
Fix hang-on-exit deadlock in VinylControlManager. This is triggered by the recent collapsing of ControlObject and ControlObjectThread.
Merge branch 'master' into DJO-mastersync

Conflicts:
	mixxx/src/library/library.cpp
Merge branch 'master' into DJO-hacks-trunk

Conflicts:
	mixxx/src/library/library.cpp
Merge branch 'DJO-hacks-trunk' into DJO-mastersync
Merge branch 'master' into master_sync_clean
Merge branch 'master_sync_clean' into DJO-mastersync

Conflicts:
	mixxx/build/depends.py
	mixxx/res/controllers/Xone-K2-scripts.js
	mixxx/src/controlvaluedelegate.cpp
	mixxx/src/engine/bpmcontrol.cpp
	mixxx/src/engine/bpmcontrol.h
	mixxx/src/engine/enginebuffer.cpp
	mixxx/src/engine/enginemaster.cpp
	mixxx/src/engine/enginesync.cpp
	mixxx/src/engine/enginesync.h
	mixxx/src/engine/ratecontrol.cpp
	mixxx/src/mixxx.cpp
	mixxx/src/vinylcontrol/vinylcontrolmanager.cpp
Add support for building in a git tree as well as bzr
Reviewed: rryan, https://github.com/mixxxdj/mixxx/pull/3
Tested: builds with both git and bzr for me
Merge branch 'master' into DJO-hacks-trunk-nodejerk

Conflicts:
	mixxx/src/library/library.cpp
Merge branch 'DJO-hacks-trunk-nodejerk' into DJO-mastersync