Analyze with Phan

Summary:
This is a static analyzer developed by Esty.

It will help to have a documentation coherent with the code.

Test Plan:
Run phan.

See P230 for output at commit time.

Reviewers: dereckson

Reviewed By: dereckson

Subscribers: alken-orin

Differential Revision: https://devcentral.nasqueron.org/D767