tower range is now hidden by default (will need to debug this cause there are still some bugs with it)
placing a building will evaluate if any path needs to be recalculated
if a path is recalculated, the units using it will stop moving a request new one!
TODO: keep track of who’s using each path in the cache. when we stop using one, tell it to the cache so it can release it! avoid bloating the cache
Added a physics body on buildings to prevent units from going through them
Path cache now holds a list of path owners and releases a path when nobody uses it anymore
Units release the path cache when they get killed or when they recalculate theirs