Added error handling example

@yawnt @jcrugzz, the reason that your wildcard error handler `ee.on('*:error', function (err) {}` does not get picked up is because it does not match the event emitted. you could use `ee.on('*:*:*:error', function (err) {}`

I do agree that the number of namespaces does seem a bit much. perhaps `ws:error` and `web:error` would be sufficient. 

Issues #462 #470