heterodyne: Correct transposition typo in recpars report.
KAPVIEW: Compression irrespective of WLIM.

For some DAS data where there are fewer than 10% good spectra, the
old code generated an error trying to draw the line plot for an all-bad
array created by COMPAVE.  By lowering WLIM to zero the same might still
happen, but it will now plot the average spectrum across a 0--10% sparse
grid.
KAPVIEW: Tidy comments.

 - Add punctuation.
 - ORACDR -> ORAC-DR
 - Use capitals for KAPPA and task names.
 - Insert a blank line before comments.
 - Wrap some comments.
heterodyne: Fix parenthesis bug.

Compiler told me about unbalanced parentheses, but dozily I removed one
instead of adding one.  The old code could lead zero histogram bins.
heterodyne:  Set minimum threshold config and rms for FINDCLUMPS.
heterodyne: Set the histogram resolution dynamically.

This aims for seven bins across the FWHM of the main histogram peak.
heterodyne: Remove trailing whitespace.
heterodyne: Report the dc offset applied to the baseline.