Make the quick create menu more or less work correctly
Summary:
Ref T3623. I'm sure I didn't get the margins / drop shadow quite right, but this looks and works reasonably well:
{F105637}
Test Plan: Clicked stuff to quick create.
Reviewers: chad, btrahan
Reviewed By: chad
CC: chad, aran
Maniphest Tasks: T3623
Differential Revision: https://secure.phabricator.com/D8089