Created AUTHORS.md

Listed Conor Mancone as the sole "author" and designated Anthony Gonzalez and Daniel Gettings as "direct contributors". Used DFM's AUTHORS.rst on emcee as inspiration: https://github.com/dfm/emcee/blob/master/AUTHORS.rst
Merge branch 'master' of github.com:dpgettings/ezgal

Forgot to pull the version with LICENSE before creating AUTHORS.md