Updated the Megeath map/cmd/cc figures to use megeath_class_column.

This partially addresses Issue #9.

The plots lose a few points, but (here's the beauty) they are EXACTLY the points we wanted to lose!
Now megeath-class period-hist uses the improved Megeath class column.

This made the code SO MUCH CLEANER. no more bizarre array indexing.
Refactored f_magnitude_hists_by_class to use the megeath_class_column.

Some minor style upgrades, too.
Made the subplots in all of these guys sharex each other.

This fixed their weird x-scaling issue where the bars got really fat -- now everything scales properly from 0-2.
Revised the docstring'd KS test value, since we changed something.

Also, now we just have the function print out a ks_2samp output as part of its normal running.