parallax support; command-line scripts

Support has now been added to include parallax (in miliarcsec) to the observable properties of a StarModel.

There are now also two command-line scripts, starfit, which allows executing an MCMC fit of a StarModel from the command line (e.g. starfit mystar where mystar is a folder containing a star.ini file), and batch_starfit, which executes many starfits at once on a cluster (currently assuming slurm is the batch scheduler, but presumably could be adjusted to any other).

Also, there was a correction made to the loglike method of StarModel such that now I believe the likelihoods/priors are properly normalized; this was not the case before.

Bug fixes

• Typo fixed in StarModel._make_samples()
• Bug fixed in StarModel.triangle() when distance is not being fit for.

Apologies to anyone trying to keep up with all these rapid changes...hopefully this will settle down shortly.

TripleStarModel added; bug fixes

Bug fix:

• When creating the StarModel.samples attribute, there used to be a hard-coded cut on lnprob that only made sense in a very limited circumstance. This has been replaced with a cut to cull the top 99.5% (as ranked by lnprob) samples.

Feature added:

• TripleStarModel, along the lines of BinaryStarModel but with three stars.

BinaryStarModel added; triangle plots tweaked.

New in this release:

• Added BinaryStarModel object, which enables fitting photometry to a model of two stars at the same distance, Fe/H, and age.
• Changed StarModel.triangle() such that if truths is provided, then extents adjust so truths can be seen even if outside requested extent range.

Distance and Fe/H priors included

Important functional changes included here are that now priors on distance and metallicity are included when doing an MCMC fit on a StarModel. The default [Fe/H] prior used is a based on the local metallicity distribution from SDSS data, and this helps big-time when you are fitting only photometry with no spectroscopic data.

Bug fixes

Fixed a few bugs from initial release. Isochrone object can now be called with distance and AV arguments; this helps a problem with double-correcting absolute magnitudes in StarModel. Also added a few more entries to extinction file so everything in Dartmouth models is covered.

Initial release

This is the first public release of the code; still testing the waters.