Allow parenthesis in author name

Summary: We have a dozen users who has (...) in their 'real name', like 'Jimmy (He) Zhang', and it's causing the diffusion file browser problems when blame is enabled. The parser does not expect those parenthesis and the lines of code will be empty if they were last touched by a user like that.

Test Plan: Try it

Reviewers: wez, lifeihuang, JoelB, #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8429