For VTOL and FW set default landing heading to takeoff heading when TakeoffMissionItem is added in PlanView

Replace qFuzzyCompare with better functioning QGC::fuzzyCompare

supportedMissionCommands is vehicle class sensitive

Show correct item editor based on current VTOL state

Fix recalc bugs associated with vtol state, speed, vehicle/gimbal yaw

Support for Vehicle and Firmware classes

Fix item initialization problems leading to crashes and incorrect profile display

Fix global alt mode support

Upload pre-check must be vehicle-class based

No need to call setMissionFlightStatus on newly created items

Initial support for global plan-wide altitude mode setting

Rework handling of fw/vehicle type with respect to conflicts with actual vehicle types.

VTOL Takeoff should be considered a transition to FW

Fix VTOL hover determination

Fix logic of when adding Landing item is allowed

Add support for Json file string translations

Major rework to support terrain profile display and terrain collision reporting

VTOL Landing Pattern support

Drag of land/loiter maintains land distance/heading as appropriate

Out Survey polygons with KML save

Much better mission->kml conversion support

Remove buggy support for generation of incomplete lines

Correct handling of terrain ready when loading back from file

Plan: Add support for takeoff item required

Fix ArduPilot fake home position handling

Mavlink terrain protocol support

Fix waypoint linkage to first item

Avoid arrow positioning with take item

Fix current item updating after delete

Fix Plan insert Takeoff/Land for correct enable state and insert into correct place. 

Update vehicle heading from possible item change

Add support for incomplete segment visuals

When a child item is current show the parent as selected