mavlink app: Clean up allocations
Converted streams to new API, saving a bunch of RAM
mavlink app: Fix compile error
mavlink app: Finish porting all messages to new scheme
mavlink: report global position setpoint and do this always no just when updated, otherwise the values are not visible in QGC
mavlink: put update call back in
Merge branch 'master' into mavlink_stack
Merge pull request #1054 from PX4/hil_pos_sp

Enable global position setpoint over USB
MavlinkOrbSubscription API reworked
Merge branch 'master' into mavlink_stack
mavlink: sign of climb rate fixed in VFR_HUD message
Merge branch 'mavlink_stack' into dataman_state