Cleanup for CFGs

Summary: Removes unnecessary code. Also makes `applyRules` `protected` for `generateClass` and D5690

Test Plan: Generated lipsum, names, some code. Tried out `generateClass`.

Reviewers: epriestley, DeedyDas

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5695