Allow users to set whether or not textareas are monospaced.

Summary:
Some users like monospaced textareas and others don't.
This introduces an option to set this as a user preference.

Test Plan: Enabled and saw monospaced textareas, disabled and saw non-monospaced textareas.

Reviewers: epriestley

CC: aran, Korvin

Maniphest Tasks: T2114

Differential Revision: https://secure.phabricator.com/D4037

src/applications/phame/controller/post/PhamePostEditController.php

@@ -132,6 +132,7 @@ final class PhamePostEditController
         ->setValue($post->getBody())
         ->setHeight(AphrontFormTextAreaControl::HEIGHT_VERY_TALL)
         ->setID('post-body')
+        ->setUser($user)
       )
       ->appendChild(
         id(new AphrontFormSelectControl())