Add Color Blind Friendly colors with colorblindfriendly.py

This script creates a series of colorblind-friendly colors (from [here](http://jfly.iam.u-tokyo.ac.jp/html/color_blind/)) that can be used to color PyMOL objects and selections.  These are unambiguous to both colorblind and non-colorblind individuals.

(Bonus: Also included are a couple of changes I made to clean up comments in elbow_angle.py but never pushed.)