Fix layer heights

More work on Structure Scan rewrite

Bug fixes for Structure Scan. Also includes support for Entrance/Exit Alt.

Add support for Start From Top/Bottom, plus more helpful stats

Remove incorrect vehicle yaw

Fixed camera shot count when trigger distance == 0

Fix Structure Height loading

Also remove custom gimbal support

Fixed bugs the unit test found

Converted Structure Scan to use CameraCalc such that it now works with
camera specs.

Fix crash when adding second structure scan