Initial fix for issue 2555
Small modifications to enable keyword retrieval
Pass requested keywords as a string.
Allow multiple --key arguments
Added align keyword argument to the pprint function, for left/right alignment of columns.
Got rid of debugger.
Generalized the new kwarg  to handle alignment on a column by column basis for multi-column tables.
Fixed whitespace errors.
Hopefully last whitespace fix.
Merge remote-tracking branch 'upstream/master'
--keyword instead of --key
--keyword instead of --key
Add mad_std function
Add fwhm_to_sigma and sigma_to_fwhm functions
Implement @embray's comments
Prepend "gaussian_" to FWHM <-> sigma conversion functions
Added instructions on setting up affiliated package manually
Added section on updating for manual set-up
Added instructions on updating astropy-helpers
Mention ah_bootstrap.py