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
edit view

Start with no polygon

New QGCDynamicObjectManager support

Get rid of QGCView, QGCViewPanel and FactPanel. All messages and dialogs are now handled in the root window.

Fix crash when adding second structure scan

Otherwise things go haywire when points are added