$D01B/53275/VIC+27:  Sprite to Background Display Priority

   +----------+---------------------------------------------------+
   | Bit  x   |   Sprite x: 0 = Sprite has higher Priority        |
   +----------+---------------------------------------------------+

   Higher Priority means sprite is in front of everything.

   Lower Priority means sprite is behind bit-combinations starting with
   1 (e.g. %1 in hires mode and %1x in multi-color mode) and in front of
   bit combinations starting with 0 (e.g. %0 in hires mode and %0x in
   multi-color mode). So we get the following priority-tables:

   Hires: Bit=0 < Sprite < Bit=1 ; Multi-Color: Bit=00 < Sprite < Bit = 10
                                                Bit=01 <        < Bit = 11