Summary: This is just a bit of gardening in order to make the responsive-UI diff easier; I'll be putting `getColorFor($status)` type things in this class, following the pattern in `ManiphestTaskStatus`.
Test Plan: Poke around Releeph.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D5893
