Linearizing communication time

[jtebert]

Uses a communication grid (with existing CollisionBoxes) to make simulation of communication linear in the number of robots.

Before merging, this needs:

• Documentation of grid and psize
• Possibly make grid size adaptable to communication range (harder)
• Make communication ranges noisy (in initialization, with some mean/std)
• Verify that communication still actually works
• Verify that it works with multi-threading

[r-barnes]

@SeymourGabe : The battery commit should probably be on a different branch.