Fixes made to the Lookup System Manager Program                22-JUL-1991 
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 8-JUL-1991 
    The calculation of the quantity TREE_OFFSET has been changed, because 
    now it has been more completely defined. The calculation now takes into
    consideration both positive and negative contributions to PX and PY.
    The changes were made to the routine DERIVE_TREE_OFFSETS.

22-JUL-1991 
    The routine COMPILE_QUANT_SLOPES had a division operater unprotected
    against divide by zero. The divisor was the geometry coordinates of the
    particular trigger tower. If the quantity were zero however, it would 
    be an indication of problems elsewhere.