R1:8c9d61bedcad

Add "assigned" and "authors" to Maniphest pro search

Summary: Ref T2625. Moves this a step toward being able to replace the current search.

Test Plan: Used search interface.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2625

Differential Revision: https://secure.phabricator.com/D6934