Heavy Waves

Halts attacking biter groups and lets them fester until a certain time when they all attack at once. Use the periods of safety to build up defenses, or clear out the nearby nests/groups before their next big assault. Also adds a new combinator found on some spawners you can use to check the status of the next wave and a non-lethal laser turret you can unlock sometime before you get artillery to mark those spawners for your defenses to ignore, just watch out for splash damage.