Fixed electro secondary limit being global

Fixed electro secondary limit being global
Now it tracks which electro entity has fired how many balls and destroys
the oldest ones of that electro entity, not the oldest of any electro
entity. I had to clone and edit the rubble functions to support entity
storing and comparing the owner of the child entity to given entity,
those are named electrorubble but can be renamed, they are just created
for electro, they support other entities too and not only electro balls.