joshspeagle
prior rework
Modify the galactic prior (and the reddening prior) to allow for faster queries when repeatedly querying the same (l,b) values (such as when fitting a single object "on the fly").
This should be done in conjunction with #39. In particular, I actually want to add functionality to simulate sources from the prior so we can generate mock datasets for future runs (for comparison with, e.g., full-sky runs over Gaia to simulate basic selection functions).
Being able to generate easy mocks is something that would be nice, and would require writing up some slightly different functions. I'm retiring #39 for now since it turns out to not be the dominant source of runtime overhead.