When viewing a change, 'n' and 'p' will jump to the next and
previous changes (respectively) from the most recent list of changes
without pushing the current change on to the navigation history.
This streamlines the process when reviewing many changes in
sequence.
Change-Id: I31d4b30cd8d7bd6f5c5c4376033e43421fbe6c5b
6678ff45b9