The impulse is fairly weak, but it has no cooldown (of course). As long
as you can reliably click on them, you can keep dragging them around.
This builds charge.

Portal now COSTS charge, rather than gaining it, so that you bully
people until you can build a portal.

You touching a wall does not do it. This encourages teamwork / using
your walls in clever ways to gain charge.

Also allow 100 walls, and removal of all walls upon death

I love git bisect! The problem was due to me accidentally deleting a
crucial condition `is_network_master` when checking for hero_switch
input.

Hero 1 fails, probably 0 too haven't checked though. Hero 2 is fine.
Haven't tested 3.

Also, levels now inherit a level object

Hero 0 speeds up especially quickly!

Currently it just switches up by one hero.

To change, I had to change the set_status rpc protocol to include
rotation (that way switching heroes isn't jarring); so they're combined
here.

Also add variation in spawn point, so that all spawns are not on top of
each other

At this point I've pretty much deleted all of Calinou's code. Oh well,
it DID get me started.