polling_done/1 added

receive_state_requests/0 now waits for a {Pid, polling_done} signal
before it exits. this signal is given by polling_done/1 in banker. I may
have to worry about sending this signal to processes which aren't being
polled.
printing in polling_done

getting blocked on lists:sort now
interestingly status() causes blocking
can't believe I didn't save sorted clients
claim/loan responds weren't formatted right
don't need NewClient_try
notify_waiting_clients() doesn't block

also moved exit catches up so as to process them first
client must wait to know it is attached
wait for banker confirmation before you run
need to do the state polling for each request

but clients enter request body only once
only notify req'r that they may move forward
caught a failure to handle unsafe case
closer to correct - checking for dead procs
timeouts provide successful completion