Compat
Update efs_easychatserver_username.rb

Add targets for versions 2.0 to 3.1.
Add install path detection for junk size calculation.
Add version detection for auto targeting.
License and Require
Use EXITFUNC
Land #3431, @bcoles's new targets for efs_easychatserver_username
Land #3426, @Meatballs1's Python v2.3.3 Compatible Command Shell payloads