Mavlink terrain protocol support

Fix initial load for Plan 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)

Fix Rally Point loading

Ignore old version 1

This time to handle correctly updating plan/fly view when plan changes

Update the user model to a single controller instead of multiple