See lengthy discussion at https://code.wildfiregames.com/rP22266
This patch does the following:
- move territory_pull.xml out of special/ to make it placeable
- insert <Visibility> node to solve Atlas errors
- convert it into a generic template (template_territory_pull.xml) with a related territory_pulls/ subdirectory for its children
- created six territory pull children (each with a Weight : Radius ratio of 1000 : 1)
- only one is used, in maps/scenarios/Campaign Test Map.xml, but the others might become useful when people start making campaigns in the future