Rework complex distance, camera shot count calc for better back compat

Should not rebuild transects for newer file formats where mission items are stored in file

Add camera start to transect entry even when taking images throughout survey area.

multiple polygons

need to fully implement vertexvisibility

[Survey transects generation] move some of the logic handling out of function that handles only one polygon

Fixed camera shot count when trigger distance == 0

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Also don't save to settings

This prevents intersection misses on more cases

Fixed bugs the unit test found