[bithorded/lib/grandcentraldispatch]Gracefully shut down.
[lib/keepalive]Change default ping response timeout to 15 seconds.
[clients/bhupload]Listen and react on disconnection.
[lib/keepalive]Send Ping with priority. If sendQueue is completely full, drop connection immediately.
[lib/connection]Only reset keepalive-loop if a message could actually be decoded.
[lib/connection]Count errors. Too many successive closes connection.