Summary:
New, cleaner, ObjectItemLists. Lots of minor style tweaks, basic overview:

 - Remove FootIcons
 - Remove Stackable
 - Remove Plain List
 - Add StatusIcon
 - Add setting ObjectList to an ObjectBox
 - Minor retouches to Headers

Mostly, this should give us an idea of life with the new Object Lists. I'll take another application by application pass down the road. This mostly looks at implementation in Maniphest, Differential, Audit, Workboards. Checked a few other areas and dialogs while testing, and everything looks square.

Test Plan: Maniphest, Differential, Homepage, Audit, People, and other applications. Drag reorder, etc.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12865