Visual tweaks for mission items

Fix command picker visuals

Support move item to previous item position

Can't hide fly through commands

Cancel ROI support plus many big fixes

More work on contextual Plan tools

Fix takeoff item insertion in plan creators

Support for new TakeoffMissionItem and Takeoff Tool 

Delete icon and Command Picker ui

Better incomplete data visuals

Wizard Mode for Create Plan

New Create Plan support

Correctly handle command changes from no-coordinate item to coordinate item

Hide sequence numbers

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.

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

Better sizing when closed

Change Command only supported for Simple Items

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml

Adjust colors
Remove unused image

Update the user model to a single controller instead of multiple

Fixed a pile of bugs as well

Also added insert pattern support to hamburger

Changed (selected) mission item color to primaryButton instead of buttonHighlight
Adjusted some colors for better contrast
Removed a few JavaScript exceptions caused by the order of object destruction