Only create one QApplication (in GUI-mode) per mixxx-test run.
Minor optimization to BeatGrid::findNthBeat.
Create long-press latching mode for pushbuttons
Make latching simply the opposite of powerwindows
Create long-press latching mode for pushbuttons
Make latching simply the opposite of powerwindows
Add testing -- fails
try to use mixxxtest with gui on.  FAIL
Fix wpushbutton latching tests
Merge remote-tracking branch 'ywwg/long_press_latch' into longpresslatching

Conflicts:
	src/control/controlbehavior.cpp
	src/control/controlbehavior.h
	src/controlpushbutton.h
	src/widget/wpushbutton.cpp
	src/widget/wpushbutton.h
Initialized m_bXXForcePush for making the test succeed