VTOL_architecture

Added vtol_att_control module which is still in the testing phase so don't expect anything to work!
fw_att_controller and mc_att_contoller now publish on virtual topics if airframe is of type VTOL. 

I don't get why you define MAV_TYPE_VTOL_DUOROTOR etc but use the quadrotor (no vtol) here. also the mav_type enum has to be updated in mavlink