R1:18cfab0c3696

Allow configuration of the default monospaced font style

Summary: This is a fairly contentious default that we can easily move to configuration.

Test Plan: Changed the default, changed my user setting, reverted my user setting, verified the "settings" page.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D2935