cuebmapping for deferred textures. blending is still all kinds of wrong ...

...IMO, but at least this version doesn't actively break anything else along the way.

Details:
1) conforms DeferredDiffuseMapHLSL::processPix to use a similar    if (  fd.features[MFT_CubeMap] ) chunk as stock diffuse.
2) adds newFeatures.addFeature( MFT_CubeMap ); in the prepass (this version does not remove them from the normal pass, as that was causing severe side-effects)
3) adds checks for    if (fd.features[MFT_DeferredDiffuseMap]) in ReflectCubeFeatHLSL::processPix

skybox and our test cube use the desertsky cubemap, while the sphere uses dynamiccubemap. note that unlike stock, dynamiccubemapping has not yet been fully ported on over to the point where it draws all objects in it's reflections.