Work on automatic convergence testing and re-sampling.
Added control parameters for sampler convergence to model_galaxy_mcmc
Refactored save_posterior_model to take only the model MCMC object (and not separate db object) since db can be accessed from the MCMC object.
Changed iteration tracking to simple for loop. Changed magic distribution creation to use getattr instead of class.__dict__
support for generating posterior images and stats from a subset of chains in database.
pep8
refactoring & comments
comment cleanup
replaced call to Model.seed() with the more-descriptive and correct Model.draw_from_prior()
Merge pull request #6 from mmechtley/feat/sample-until-converged

Feat/sample until converged