fix wrong logging logic etc

log level takes affect for ffmpeg and libass log
TODO:
remove qDebug() in headers
different function type error(android)
misuse export macro
new: orientation support in qml

only for opengl mode
TODO:
point mapping, roi(use a matrix in
VideoRendererPrivate?)
test other classes
Merge remote-tracking branch 'upstream/master'

Conflicts:
	qml/QmlAV/QuickSubtitle.h
	qml/QmlAV/QuickSubtitleItem.h
	src/QtAV/VideoOutput.h
	src/filter/SubtitleFilter.cpp