OpenNI2-FreenectDriver: reduce compiler warnings

Signed-off-by: Benn Snyder <benn.snyder@gmail.com>
OpenNI2-FreenectDriver: support ONI_STREAM_PROPERTY_AUTO_WHITE_BALANCE and ONI_STREAM_PROPERTY_AUTO_EXPOSURE

Signed-off-by: Benn Snyder <benn.snyder@gmail.com>