All decisions were done deep inside the texture creation code, leaving zero options to the higher level code for controlling the feature.
Changed this so that the option to upscale must be passed as a parameter to FRenderState::SetMaterial and extended all needed variables to manage the added texture variants.
Still not solved: Material layers need explicit control, not only for scaling but also for filtering.
It makes little sense exposing every minute detail of this through UDMF.
Setting it up that way is far too complicated. Using virtual textures that map to a real texture plus a colorization record should be far easier to use by mappers.
This also doesn't piggyback on the Doom64 color feature anymore and is completely separate, despite some redundancies.
This is still missing the texture definition part, though.
