Before you can use the system to detect collisions between GELS, you must
allocate and initialize a table of collision-detection routines and place
the address of the table in the gelsinfo.collhandler field.  this table is
an array of pointers to the actual routines that you have provided for
your collision types.  You must also prepare some members of the vsprite
structure: collmask, borderline, hitmask, and memask.