gfx_elements now have a xor mask that is applied to each source bit offset when decoding. This can be used to deal with endianness when decoding gfx from RAM or from program ROMs, or to reverse the bit order sense when this is useful (e.g. pgm.c) [Alex Jackson]

(nw) This is test/checkpoint right now, final goal is to automatically determine the appropriate xor at startup when the gfxdecode info is processed (e.g. based on the width and endianness of the ROM region)