Invaders can spawn in immobile formation

[sparr]

http://screeps.com/s/wmfAZA

The heal creeps are blocking the ranged creeps, and won't move until the ranged creeps do.

A quick fix would be for invaders to keep track of how long they are stationary and make a random move if they are stuck for more than a few ticks. This would also make them less predictable and deterministic.

[Sergey]

Fixed, thanks.