CluStR rewrite!

[sweverett]

Now that CluStR is being used by the group again it's time for some updates! Or rather, let's use all that learned python/astro knowledge of the past 3 years and write a new, simplified, more extensible, and more general code base that wraps Kelly's linimx package for regression on arbitrary columns in fits catalogs. We'll still need to implement some cluster-specific features but this can be accomplished with a pre-existing config structure such as yaml.

This will also serve as a summer project for Paige (will link once she has an account!)

Here's a TODO list that we will update as needed:

• Combine different cluster files into a single clustr.py (@paigemkelly @jjobel)
• Setup new environment file, config file, and IO processing (@sweverett)
• Make new main() function w/ object-oriented structure
• Implement all new classes:
• • Config
• • Catalog
• • Data
• • Fitter
• Implement new flag structure used by Config in Catalog or Data to apply cuts (@sweverett)