Hardcode the few remaining palette references instead. We might want to
include some method to customize some colors again, but not for debug
display and such things.
Both classes did the same thing at the same time, with the only difference
that C4GUI::Resource was vaguely more associated with GUI stuff. Some
time ago, C4GUI::Resource could be freed during the game, but not anymore.
This saves some lines of code and one redundant class, but shouldn't change
anything besides progress bar being textured a little earlier during
startup.
This is a whitespace-only patch. Hopefully, it'll only affect rarely-changed
parts of the engine, since all regularly maintained pieces should already
use tabs.