Fix for chdkptp colors on IXUS120 from waterwingz:
http://chdk.setepontos.com/index.php?topic=650.msg101479#msg101479
enable CAM_AV_OVERRIDE_IRIS_FIX for sx210is, fixes Av overrides per report in http://chdk.setepontos.com/index.php?topic=10132.msg101514#msg101514
comment on is_raw_enabled for resolution == 5