It may use the same calculations as the hardware renderer but must use the 2D drawer for display.
It should be investigated if the hardware renderer can do this as well.
This also replaces DTA_ColormapStyle with proper implementations of its components. As implemented it was a very awkward mixture of various effects that already existed in a separate form. As a result of its implementation it required additional but completely redundant shader support which could be removed now. As a side effect of this change a new DTA_Desaturate option was added.
