WMF: enabled HW-accelerated video decoding for the QML video item.

WMF: enabled HW-accelerated video decoding for the QML video item.

It also applies to QGraphicsVideoItem when used on a GL viewport.
We now have a new video sink that is based on Microsoft's EVR sink, we just
replace the default Presenter with our own. Frames are rendered into D3D
surfaces using DXVA, then copied into a shared D3D/EGL surface and finally
bound to a GL texture to be used by the video surface.
The shared D3D/EGL surface is a feature provided by ANGLE and therefore Qt
must be compiled with ANGLE for this new video sink to be compiled and
used.

Change-Id: I0b7b9968eed5488f9ef1a2dcca5213bd0af232ab
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>