removed unused function crashDlg()
renamed MixxxApp to MixxxMainWindow, because it is derived from QMainWindow and not from QApplication
Introduced a MixxxApplication class derived from QApplication
Almost working version of global mouse point emulation
mouse click fake works but issues with drag and drop
fixed drag and drop issues by faking a touch release
Merge branch 'master' into singletouch

Conflicts:
	src/mixxx.cpp
	src/widget/wwidget.cpp
Merge branch 'master' into features_effects

Conflicts:
	src/basetrackplayer.cpp
	src/main.cpp
Comment run. Remove locking from places that won't need it anymore.
Change terminology of TwoWayMessagePipe to use 'receiver' instead of 'target'.
Refactor TwoWayMessagePipe to separate the sender and receiver so they can't call each other's methods.
Get rid of EngineMaster::getEffectsManager().
Add BaseReferenceHolder/ReferenceHolder for holding a reference without being coupled to it.
Add EngineEffectsManager, an engine-side representation of the effects subsystem. It communicates with EffectsManager via a TwoWayMessagePipe with EngineEffectsManagerRequest and EngineEffectsManagerResponse messages.
Shorten message class names.
Add simple EngineEffectChain implementation.
Re-structure messages to use unions (again). Non-POD can be stored outside the union.
Handle add/remove effect chain messages in EngineEffectsManager.
Add a set-parameters request for EngineEffectChain and handle it.
Add EffectRequest processing/dispatch loop.