Visual tweaks for mission items

Cherry pick from master

Better error message

Add note about ADSB server settings

Correct handling of terrain ready when loading back from file

More changes to ArduPilot manifest lookup

Unit Test for Survey command sequence generation

Major rewrite of Survey generation for simplicity. Also includes support for CONDITION_GATE.

Temporary use setting for using CONDITION_GATE in Patterns

Unit test for mission transfer error string checking

Much better error reporting for Mission transfer errors

Plan: Add support for takeoff item required

Handle multiple file extensions correctly

Shape file examples for testing

Programmatic switch to SetupView leaves two buttons selected

Better error text

Give up on getting AUTOPILOT_VERSION based on time now retry count.

Wizard mode should be off for loaded items

Clear wizard mode when loading from file

Change default to on

Flight mode fix, cherry picked from master

Added correct handling of mavlink 2 change based on capability bits

Fix empty Plan File dropdown display

Fix even more bugs