Fixed and Optimized timer events

FIXED - Timer events after reconnect
  since timer events started only on first client connecting,
  a socket.io reconnect (such as closing the server and starting again)
  required a client restart to get the events back.

Optimized - Timer events are no longer sent if no one is connected
  Check connected client count on "connect" and "disconnect" events
  count === 1 => first client just signed in, so start emitting events
  count === 0 => last client just left, stop emitting events