09/20/89 - JR - REFCALC.C
                in function subtract_reference(), changed test against
                ADJ_BADFLOAT from <= to < so it will subtract the mean only
                in the latter case
06-29-90 - JR - *.C:
                switched #includes to common.h in order to avoid
                problems when switching compilers
07-02-90 - JR - *.C:
                removed typing in function arg list for Sun
              - MATRIX.C:
                removed #define imatrix(i,j) -- Sun cc compiler doesn't like it
04-19-93 - EF - deriv.c: 
                function deriv1 was changed to check for zero in the denominator.