…n slices of a dset with slice planes to be black/opaque instead of transparent.

…ERLAYS structure to prevent thri getting confused with unrelated variables with similar names. Moved them to the SUMA_SurfaceObject structure instead.

…A_X_SurfCont structure. This is to avoid confusion with fields of similar names but different functionality

…t confused with the unrelated AlphaThresh variable in the SUMA_OVERLAYS structure

Fixed bug where one surface tends to be lighter when both hemispheres loaded

…bably with button being checked when variable opacity not active, and unchecked when it is, with alternate surfaces

…e of variable overlay opacity for one of multiple surface objects. One problem is that switching objects autommatically switched variable opacity off."

…with extra black space when durface changed in multi-sruface dataset

…threshold opacity is true. This was not the case when the surface was changed with DriveSuma

…tatus of the variable sub-threshold opacity when DriveSuma was used to turn the variable opacity on and off

…urface control menu lengthening when the surfaces are switched. Also tests "A" button being turned on and off and given different opacity falloff functions

…nt planes and for standard test for variable opacity. Also removed some no longer used debugging output