R1:261a4a0e51fd

Add inline comment counts to the filetree view

Summary: See PHI356. Adds inline comment and done counts to the filetree. Also makes the filetree wider by default.

Test Plan: Fiddled with filetrees in different browsers on different revisions. Added inlines, marked them done/undone.

Differential Revision: https://secure.phabricator.com/D19041