Move the buglist override to as early as possible, include switches for specific rendering backends on windows

Removed incorrect Vehicle.altitudeWGS84

Also added Center to Mission support

For issue #2776

This allows you to click/add waypoints under the list view

Plumb through initial object mode on Vehicle

It is also no longer a user visible field

# Conflicts:
#	src/MissionManager/MissionManagerTest.cc