initial upload of Will's cosmo code

This code contains many basic cosmology dependent functions (e.g. cosmological distances, time scales, density, etc.).
initial upload of Will's tools code

This code contains many generically useful functions (perhaps too many for one file, should think about breaking it up).
This code is often a dependency of other codes.
initial upload of Will's profiles code

Currently this code includes useful function for calculating various properties of NFW halos and
filament density profiles.