R1:4d4b4f483702

document running phabricator on builtin PHP webserver

Summary: This is based on info from https://github.com/facebook/phabricator/pull/165

Test Plan: View configuration guide

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3467