Merge remote-tracking branch 'gerrit/dev' into highdpi

Conflicts:
	src/gui/kernel/kernel.pri
	src/gui/kernel/qsurfaceformat.h
	src/gui/kernel/qwindow.cpp
	src/gui/kernel/qwindowsysteminterface.cpp

Change-Id: I1465f2b7c654c58560b2678af44031fabaf5b257