Reuploaded at same link, added ini file where you can choose a) summon single stack so at each cast creatures are added to initial stack, or b) summon the regular way, each cast a new stack. Also added 2 choices to learn the spell, a) timer giving it if hero doesn't have, or play your chance and have it from mage guilds (10% chance/town)
Was interesting coding summon unique stacks, I found that is a nightmare to keep track of a dead summoned stack. Scratched my head for 2 hours.