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. 
Added rc.vtol_apps and rc.vtol_defaults.

TODO: In rcS the MAV_TYPE variable for the VTOL case was so to 0 which means generic. There should exist a MAV_TYPE for VTOL!

Is the fixed wing mixer missing here?