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EXIT FIELD MAPS $1D3166-$1D4904
pointers: $1D2D64-$1D3165
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byte 1  low byte of area pointer
byte 2  lower bits: high byte of area pointer
	upper bits: area format flag (tells it what type of area is being entered)
	bit 4	turn into classic NES Mario (only used at Booster Tower)
	bit 5	Overworld area
		extra byte(s): 3 bytes to set Mario's coordinates
	bit 6	World Map area
	bit 7	+1 unit width
		extra byte(s): 1 for field width

fields that point to a World Map area AND do NOT have a width greater than 1 unit are 5 bytes each
fields that point to a World Map area AND have a width greater than 1 unit are 6 bytes each
fields that point to an Overworld area AND do NOT have a width greater than 1 unit are 8 bytes each
fields that point to an Overworld area AND have a width greater than 1 unit are 9 bytes each

so an exit field is either 5,6,8 or 9 bytes long

byte 3	horizontal planar position of exit field (from left)
	bit 6
	bit 7
byte 4  vertical planar position of exit field (from top)
	bit 7	Z Coord +1/2
byte 5  lower bits: elevation of exit field
	upper bits: height of exit field
byte 6  horizontal planar position of Mario at entered area's entrance
byte 7  vertical planar position of Mario at entered area's entrance
byte 8
  bits 0-4  height of Mario from ground (00-1F)
  bits 5-7  radial position of Mario at entrance (ie. facing direction)
   00  right
   20  down-right
   40  foward
   60  down-left
   80  left
   A0  up-left
   C0  up
   E0  up-right
byte 9	lower bits: field width, if +1 unit width flag set
	upper bits: which way the exit field faces
	0x  down-right / up-left
	8x  down-left / up-right