Add "Combined view".

- Don't show combined mailboxes with regular mailboxes in the mailbox list.
- Add "Combined view" to the account selector instead.
- "Combined view" has all the combined mailboxes and accounts.
- Renambed these combined boxes.  (e.g. "Combined inbox" -> "Inbox")
- Regular account view still has "Starred" mailbox, but it's actually
  "combined" and not per-account.
- Re-order special mailboxes per latest wireframe.

Bug 3138004

Change-Id: I4c5860c6774b10c55ba0ca599373e51105432cf8
1 file changed