Set a ioloop instance variable in TwistedProtocolConnection.
Set a ioloop instance variable in TwistedProtocolConnection.

Even though it's not used directly to manage the connection state, its
presence is necessary for heartbeating to work. While at it, lose the
TCP connection in when asked to disconnect, which is what missing too
many heartbeats does. Fixes #83.

knowsis/pika,pika/pika,zixiliuyue/pika,jstnlef/pika,vrtsystems/pika,fkarb/pika-python3,hugoxia/pika,renshawbay/pika-python3,benjamin9999/pika,skftn/pika,shinji-s/pika,Tarsbot/pika,Zephor5/pika,reddec/pika,vitaly-krugl/pika