Use higher precision (float64) when computuing stdev in meanclip
meanclip's mean calls also needed float64; add dtype keyword; default minclip=0.001
v2.2.1
Add models.dust.acrit
Add mass support to SolarSysObject.
Fix graphics.circle fatal crash.
Add ax keyword to circle; Change default font size for niceplot.
Added planet masses to ephem.
Add La Palma, timezone (pytz) fix
Coma uses SolarSysObject init (need to do same for others), Afrho1 checks.
Fix state2orbit crash
Spitzer IRAC updates to remove old astropy.units behavior
v2.2.2
Update asteroid flux estimate examples.
Merge branch 'master' into irtf