Make Enter key work to trigger the comment buttons

The functionality of a comment button ('Edit',
'Save', 'Discard', 'Cancel', 'Reply...',
'Reply Done') is now triggered if the button is
focued and Enter is pressed.

Bug: issue 712
Signed-off-by: Edwin Kempin <edwin.kempin@gmail.com>
Change-Id: I0448bb44fab85025a825a6963780a710e0dcde6b
3 files changed