Small bug fix for 5 stars

On special missions like full house and other random missions that limit the total number of towers that you place on the map, the counting is off. It always blocks the towers one before the limit. So on full house you can only place 4 towers instead of the said 5. Just played a random mission that allows 9 towers max but I could only place 8. Please fix. Everything else is great!!

So close!!! about Bloons TD 5