Peebee

- Added fitter.py module

- added alos_obs(), pbdot_intr(), and intr_over_gr() to convenience submodule

- had to rework how some decorators work to avoid circular imports
- fix_arrays is now in glob.py (new)
- convert_to_frame is now in transforms.py
- some bug fixes so that the decorators also worked for methods (python3 fix your game)
- added some useful constants to glob.py

- borrowed some coordinate transforms from mwahpy
- added transforms module
- added convenience.pdot_shk() and convenience.dm_over_bary_alos()
- added decorators module
- borrowed the fix_arrays decorator from mwahpy
- added convert_to_frame decorator for generic frame transformations (currently supports 'gal' and 'cart')

- added convenience module
- added pbdot_gr() function
- did some sphinx testing

- added potential models, plus .accel() and .alos() capabilities
- added generic gala and galpy potential wrappers
- added sphinx documentation generator