Add ActionBar to MailboxList

Note: This does not appear in UX wireframes, this activity is going
away eventually, but it's a good testbed for ActionBar to be tried out.

Open issues:
1.  Waiting for progress indicator support, using unattractive hack
2.  Subtitle doesn't seem to work so putting account name in title
    (which is the wrong font size for phone portrait mode).

Change-Id: Iee3cac7d4f30ea210bd8f3838b69ed12cd498375
1 file changed