d3d: Begin centralizing framebuffer management.
Merge pull request #6866 from unknownbrackets/d3d9

d3d: Begin centralizing framebuffer management
Revert "Set NSPrincipalClass to get retina widget rendering on OS X"
Merge pull request #6867 from hrydgard/revert-6835-principal_class

Revert "Set NSPrincipalClass to get retina widget rendering on OS X"
Qt buildfix.
D3D9: Add support for D3D9Ex, which has faster flipping and an option for lower latency, and some other stuff.

MANAGED textures are not allowed though so compensate for that by making them dynamic for now.
D3D: Remove now-redundant texture coord scaling now that we decode the 8-bit and 16-bit formats in the vertex decoder