More work on mission item indicators

Only hide generic waypoint indicators

Remove child item display

Not draggable in Fly View

Toggle Rally Point insertion on/off.
Highlight current Rally Point and current Waypoint.
Use tab bar instead of a row of radio buttons for selection (Mission, Fence, Rally).
Fix QGCHoverButton to handle proper checked state toggle.
Get rid of the many arrays used to define behaviors for the ToolStrip. They are now all defined within its model.
Fixed color for disabled text within ToolStrip (it was invisible)

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