skins2: extend --[no]-qt-video-autoresize to skins2

As for qt4, offering the possibility to deactivate automatic resizing
is desirable. Reusing the qt parameter is not a problem for skins since
qt4 is a prerequisite.

TODO, rename this parameter with a more interface agnostic name since
the need is for all interfaces.

modules/gui/skins2/controls/ctrl_video.cpp

@@ -41,6 +41,10 @@ CtrlVideo::CtrlVideo( intf_thread_t *pIntf, GenericLayout &rLayout,
 {
     VarBool &rFullscreen = VlcProc::instance( getIntf() )->getFullscreenVar();
     rFullscreen.addObserver( this );
+
+    // if global parameter set to no resize, override skins behavior
+    if( !var_InheritBool( pIntf, "qt-video-autoresize" ) )
+        m_bAutoResize = false;
 }