Made skincolor blends more even for colors that have duplicate indices
Boss flashes are more accurate to how Software does them -- in particular, TC_METALSONIC now remaps the blend image to Cobalt, then inverts the dark blue (but leaves black alone). This means that Metal Sonic boss can use a similar blend image as his character & it will look identical to his character.
All blends that don't use the blend image at all can now work without needing to supply one (not sure if I implemented this well, please scrutinize)
