New message view command layout

UI Changes:
- "Move", "Delete" and "Mark as unread" became action bar commands.
- The message view bottom panel now only has "newer" and "older" buttons,
  with  the current position in the message list.  (shown as POS of TOTAL)
- The buttom panel is now shown only on portrait

Non UI changes
- MessageOrderManager now keeps track of the current cursor position
  as well as the total message count.

- Fixed the "move_action" string, which was wrongly marked as non-translatable.

Bug 3169454

Change-Id: I599543f9e11000a4ee283d31fbd407b2ab53ac44
1 file changed