Allow user to specify list of seeing calibrators

[dannygoldstein]

Request from @nugent68.

In estimate_seeing (and the call to it from make_coadd) update the interface to allow the user to pass a custom catalog of seeing calibrators in astropy table readable format, or a PipelineFITSCatalog object.

[nugent68]

I hope this works the first time (it never works the first time...)

[wyn18612139721]

I cann't install these four files.(psql,sextractor,swarp,hotpants) And the swarp has couldn't be downloaded.