Add ANGLE as a 3rdparty library to Qt.

ANGLE is a component that implements the OpenGL ES 2.0 API on
top of DirectX 9. See the following for more info:

http://code.google.com/p/angleproject/



ANGLE is now the default configuration on Windows. If you
want to use desktop OpenGL, you should build Qt with the
following configure options:

    -opengl desktop

To configure Qt to use another OpenGL ES 2 implementation,
you should use:

    -opengl es2 -no-angle

Task-number: QTBUG-24207

Change-Id: Iefcbeaa37ed920f431729749ab8333b248fe5134
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>