Provide more structure to PHUIObjectBoxView

Summary:
Three changes here.

  - Add `setActionList()`, and use that to set the action list.
  - Add `setPropertyList()`, and use that to set the property list.

These will let us add some apropriate CSS so we can fix the border issue, and get rid of a bunch of goofy `.x + .y` selectors.

  - Replace `addContent()` with `appendChild()`.

This is just a consistency thing; `AphrontView` already provides `appendChild()`, and `addContent()` did the same thing.

Test Plan:
  - Viewed "All Config".
  - Viewed a countdown.
  - Viewed a revision (add comment, change list, table of contents, comment, local commits, open revisions affecting these files, update history).
  - Viewed Diffusion (browse, change, history, repository, lint).
  - Viewed Drydock (resource, lease).
  - Viewed Files.
  - Viewed Herald.
  - Viewed Legalpad.
  - Viewed macro (edit, edit audio, view).
  - Viewed Maniphest.
  - Viewed Applications.
  - Viewed Paste.
  - Viewed People.
  - Viewed Phulux.
  - Viewed Pholio.
  - Viewed Phame (blog, post).
  - Viewed Phortune (account, product).
  - Viewed Ponder (questions, answers, comments).
  - Viewed Releeph.
  - Viewed Projects.
  - Viewed Slowvote.

NOTE: Images in Files aren't on a black background anymore -- I assume that's on purpose?

NOTE: Some jankiness in Phortune, I'll clean that up when I get back to it. Not related to this diff.

Reviewers: chad

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D7174