Ability to "Create X" from wide sidebar buttons

Summary: Shorten home to 240, 3 items wide, add create button for certain wide apps.

Test Plan: Test in FF, Chrome, IE8/9

Reviewers: epriestley, btrahan, codeblock

Reviewed By: epriestley

CC: aran, Korvin, vrana

Differential Revision: https://secure.phabricator.com/D4555