`torch-dokx` documentation for `fbcunn`

Summary: See http://facebook.github.io/fbcunn/fbcunn/

Test Plan: unit tests pass.

Reviewed By: soumith@fb.com

Subscribers: jhj

FB internal diff: D1739284

Tasks: 5822357

Signature: t1:1739284:1418624083:8bc81e7f7813c58c00777ffe820bf5fdc96f98b8
Script to update GitHub `fbcunn` documentation

Summary: doesexactlywhatitsaysonthetin

Test Plan: Used it to generate http://facebook.github.io/fbcunn/fbcunn/

Reviewed By: soumith@fb.com

Subscribers: jhj

FB internal diff: D1739286

Tasks: 5822357

Signature: t1:1739286:1418624148:49402a3397cb3a2e2111f1dc140e5a0824e9cf49