Rework Fly View into separate layers which can be customized at each layer.

More FlyView encasulation. Make QGCPipOverlay completely self contained

This will allow sub users to see if the ROV is in the Roll/pitch toggle
mode using the APMSubInfo section in the info widget

More work on encapsulation in Fly View

Fly View: Move business logic inside controls

More work on crash fixes

Fix unit test crash

Add support for Json file string translations

Major update to simplify and document the custom build example

New LandingComplexItem base class for landing patterns

Fix OSX compile

Major rework to support terrain profile display and terrain collision reporting

Propagate opacity and interactive properties to mission items
Set opacity to 0.5 for items that are not part of the current
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