Customers are now atoms so we can easily change them.

Fixed logic of "serve-next" (which is incrementing now-serving sign)

Made servers into agents so they can compute their (fib (rand-int 50))
in another thread and not hold up the system (yay synchronocity)

Serve now applies to a server agent and takes in a customer key:
(send! (dequeue! freeServers) (serve key))
^our serve concept is broken atm, NEED TO FIX!!!