Sprite Binary Format
--------------------

offset | name      | type    | description
-------+-----------+---------+------------------------------------------------
+000    height      Word      height of the sprite in pixels
+002    width       Word      width of the sprite in pixels
+004    type        Word      type of sprite.  Currently may be only 0 or 4
+006    size        Word      size of the entire sprite in bytes
+008    right       Word      offset to the start of the right-facing code
+00A    left        Word      offset to the start of the left-facing code
+00C    return      Code      a JML to the address at GTE_GetSPreturn()
+010    remove      Code      a JML to the address at GTE_GetSPremove()
+014    base        Word      base address for all absolute addresses
+016    guard1      Word      absolute value of base + remove
+018    rlines      Array     an array of 'height' words pointing to code segments
+XXX    guard2      Word      absolute value of base + remove

If right == left, then this sprite does not have a separate left-facing image
and the structure is compressed

Right-Facing Only
-----------------

offset | name      | type    | description
-------+-----------+---------+------------------------------------------------
+XXX+2  rheader    Code	      Header code for right-facing image
+XXX+4  rdisp      Word       absolute value of base + rlines
+XXX+6  code	   Code	      generated code


Right and Left Images
---------------------

offset | name      | type    | description
-------+-----------+---------+------------------------------------------------
+XXX+2  llines      Array     an array of 'height' words pointing to code segments
+YYY    guard3      Word      absolute value of base + remove

+YYY+2  rheader    Code	      Header code for right-facing image
+YYY+4  rdisp      Word       absolute value of base + rlines
+YYY+6  lheader    Code	      Header code for right-facing image
+YYY+8  ldisp      Word       absolute value of base + llines
+YYY+10 code	   Code	      generated code

+size	end