Adding CFG for PHP, C-like languages

Summary:
This produces only code that can never survive compile time nor lint/checkstyle.

badassery

Implemented common language traits for C-like languages (I don't consider language derivation, only the looks of code). I learnt today: PHP = C + `$` + Classes. I know I forgot many elementary structures like loops, and three-fourth of the OO stuff. Well, it's not like somebody's going to teach programming with this CFG.

I plan to add one or two other languages and make this reasonably generate diffable output (so we don't compare a function with a class).

Test Plan:
P791
P792
P793
Run away, Java: P794

Reviewers: epriestley, chad, btrahan, DeedyDas

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2903

Differential Revision: https://secure.phabricator.com/D5685