Removes a lot of hacks, especially around manipulating size (no more sizeHint(), very limited use of doComponentsUpdate and updateGeometry() ),
Simplify the number of starting options of the interface
Fixes crashes due to QStackWidget limitations
Still a lot of debug around, but mostly commented out, that will go in future commits
Close #3401
Close #3210
Close #3332
Close #1717

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>