Fixed a crash when trying to homogenize more than two sectors.

- How this mistake doesn't cause a LOT more crashes is beyond me.

Source/source/misc_structs.h

@@ -1498,8 +1498,8 @@ class asset_manager {
  total_uses--;
  if(it->second.uses == 0) {
  do_unload(it->second.ptr);
+ list.erase(it);
  }
- list.erase(it);
  }
 
 };