Accounting for image coordinate system in output catalogue

[JonahDW]

I've been running PyBDSF on some images in Galactic coordinates, which works fine for source fitting, however the output catalogue does not seem to account for this fact, reporting Galactic latitude and longitude in the 'RA' and 'DEC' columns.

I'm guessing this scenario is not necessarily accounted for (unless I have missed something!), but maybe it will be useful to somehow address this. I guess transforming everything internally is probably a pain (including source shapes etc.), but maybe 'RA' and 'DEC' could be replaced by 'GLON' or 'GLAT' in such cases?

[darafferty]

Thanks for raising this issue -- you're quite right, the output catalog always assumes that the coordinates are RA, Dec. I'll make an PR to implement the fix to the column names as you suggest.