v1.2.0

Thanks to everyone that contributed by raising issues and doing pull requests

• Check that packets still exist when we resume - @alsm
• Use monotonic time for keep alive - @johnhydroware
• Don't clean up if Autoreconnect is true - @dambrisco
• Fix race condition found by race detector - @take-cheeze
• Remove the ready field from token which means less locking - undefined
• Don't short circuit Disconnect() just because of internal state - @alsm
• Protect the router channel from double closing - @alsm
• Handle errors when reading packets - @akokhanovskyi
• Correctly strip off $share/ from shared subscription topics - @alsm
• Fix according to Juho Ha findings: the channel of time.Timer should be drained only when the program is not received from the channel. - @an2deg
• Copy the callback handler before we invoke it in the go routine - @alsm
• Only cleanup messageids if cleansession is set - @alsm
• Order the filestore files when resuming by modified time - @alsm
• Support ConnectTimeout on websocket connections - @alsm
• Fixed timer leakages in Token.WaitTimeout() - @an2deg
• Ack Qos1/2 messages after the handler has returned - @alsm
• Fixed "close of nil channel" when calling Stop() on a not connected client - @an2deg
• Don't call the internal disconnect() if not connected - @alsm
• Include http.Header in normal ws connection - @alsm
• Add SessionPresent() to ConnectToken - @alsm
• Only consider connected after connecting - @alsm
• Fix data race in reconnect - @alsm
• Adding a nil check to net.go. - @ricardoatsouza
• Add ability to use per broker credentials - @amenzhinsky
• Add support for setting the Mosquitto bridge-connection option - @dmiller-tibco
• slight adjust to make Token interface mockable - @estutzenberger
• Add is connection open method to interface - @odedva
• Add option for setting additional HTTP headers in WebSocket handshake
• Improve broker address parsing - @amenzhinsky