D3D: Set the geometry shader for triangle primitives.
PixelShaderGen: Sample the correct texture slice.
D3D: Recreate the framebuffer when stereoscopic 3D is toggled.
PixelShaderCache: Add texture array support to static shaders.
PSTextureEncoder: Add texture array support.

We only read the first slice, because EFB2RAM doesn't support texture arrays.
D3DUtil: Use a geometry shader to clear all slices.