Modifying way that completeness calculation is made in bayestar.
Different tweaks to PS1 and 2MASS magnitude limits now implemented.
* PS1 gets +0.16 mags to mag limit (same as before).
* 2MASS get +0.20 mags to mag limit, and width of completeness
  curve is 0.30 mags (vs. 0.20 mags for PS1).