Provide the first version of the Raspberry Pi autofocus algorithm. This implementation uses a hybrid of contrast detect autofocus (CDAF) and phase detect autofocus (PDAF) statistics. PDAF is always preferred over CDAF due to having less "hunting" behavior. Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com> Signed-off-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: David Plowman <david.plowman@raspberrypi.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>