[daip] Using source models in FRING

[Chris Flatters]

I mistyped: 

> I looks as if the tolerance should be 1.0E-7 in the calls to GRDFRQ. This is
> close to the expected round-off error in computing the gridding error in
> single-precision.

1.0E-7 * DF

	Chris Flatters
	cflatter at nrao.edu