(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters
- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

(svn r2866) Move all functions and tables which aren't directly involved in managing the sprite heap to a new file gfxinit.c.
This doesn't ease the global variable mess, but makes the distinction between sprite heap and gfx loading routines easier.

(svn r2845) Remove sprite size caching, it was unused
This makes GetSpriteDimension() superflous, because now it's just a thin wrapper around GetSprite() returning only part of the information, therefore remove it too

(svn r2833) Remove saving of sprite cache data:
the benefits are questionable, it's error prone, undocumented and hasn't been widely used for ages, if ever