added Publish() spec to README.md PubNub Doc.
added Publish() spec to README.md PubNub Doc.

jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api,jamesward/pubnub-api