Upgrade ANGLE to DX11 Proto

Upgrades ANGLE to dx11proto (dx11-MRT-support tag), which splits out support
for DirectX9 & DirectX11. The DX9 codepath is used by default;
CONFIG+=angle_d3d11 must be passed to the ANGLE project to build for DX11.
Existing patches to ANGLE have been updated (or removed if no longer
needed), and a patch has been added to make DX9/DX11 codepaths mutually
exclusive.

Change-Id: Ibe13befadb94f04883eca449d0ee1f0da955ff92
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Axel Waggershauser <awagger@gmail.com>