VIsual tweaks

Fix  incorrect supportsTerrain reference

Initial support for global plan-wide altitude mode setting

New wizard done model

Always how command description. Better support for VTOL Takeoff. New help text for altitude on Land commands.

Mavlink terrain protocol support

Plan: Make PX4 VTOL takeoff work like fixed wing

Use consistent "Launch" naming

Better wordings for Takeoff item

New user model for Takeoff item

Support for new TakeoffMissionItem and Takeoff Tool 

Wizard Mode for Create Plan

Update all files that use a QML Menu item to QtQuick.Controls 2.4 to solve the issue of a menu showing up in random places on Android.

Support for new AltitudeFactTextField

AltMode visual tweaks

Alt Mode: Wording changes, checkmarked menu

Altitude Mode terminology cleanup

Use correct terminology for Altitude values

This was too confusion to expose since QGC currently does not support ArduPilot terrain tile send.

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml