remove coordinator

Instead of coordinating and selecting a master, servers can all broadcast
and clients can connect to whichever one they choose.
use published versions of gems

master seems to be broken right now
add celluloid-zmq extensions
add server heartbeats
add server failure detection for clients
strip zensu.rb to minimum

Will re-add things as needed.
minimal client and server supervision groups
rename Broadcast to RemoteNotifications
add basic broadcast and subscribe
only start sub socket when peers are available
use local celluloid gems

logging, socket monitors not merged yet
use incident logger
add socket monitors to zmq notifier