add recent apps GB style action to navbar buttons (1/2)

This will add the option to open the Gingerbread style
recent application dialog.
This is the dialog that will show when doing <Alt><Tab> with
a bluetooth keyboard.

Change-Id: Id7894b698c43683467d7e8283b4b2b3dd1946f87
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>