d3d9: Update some not-yet-used ps uniforms.
d3d9: Add stencil and blend replacement helpers.
d3d9: Disable color doubling without tex.

As the PSP does.
d3d9: Fix fbo tex clamp (usually shadows.)
d3d9: Replace alpha and premultiply blend.

Unfortunately they are fairly tied together.
d3d9: Add BindFramebufferColor().
d3d9: Specify tex stage for binding framebuf color.
d3d9: Oops, can't use shader blending anyway.
d3d9: Enable 9ex, but not slower flip.

But maybe it's not slower?  Needs more testing.
d3d9: Mask out alpha using KEEP stencil op.
Merge pull request #6934 from unknownbrackets/d3d9

Update the Direct3D pixel shader to be more like GLES