remove "seen" event from Pub.

too complicated. if anyone wants this they can do it themselves.

README.md

@@ -104,9 +104,6 @@ let pub = relay.publish(event)
 pub.on('ok', () => {
   console.log(`${relay.url} has accepted our event`)
 })
-pub.on('seen', () => {
-  console.log(`we saw the event on ${relay.url}`)
-})
 pub.on('failed', reason => {
   console.log(`failed to publish to ${relay.url}: ${reason}`)
 })