Access wallnum

When 'using' a wall or sprite that needs access, it checks to see if the player has the correct access card and then starts the access animation by setting access_incs to one. It also sets the access wallnum or access spritenum to itself.
For sprites, the access card animation takes on the palette of the 'target' access sprite. got_access bits are UN-set for the access after it is granted:
pal: 0 bit 0
Pal: 21 Bit 2
Pal: 23 Bit 3