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
Merge branch 'master' into mavlink_stack
MavlinkOrbSubscription API reworked
Merge branch 'master' into mavlink_stack
mavlink: sign of climb rate fixed in VFR_HUD message
Merge pull request #969 from PX4/mavlink_stack

Mavlink stack usage improvements