* Merge patch from Nigel S, improving heartbeat accuracy (https://github.com/jasonrbriggs/stomp.py/pull/95)
* Merge various patches from Ville S (including):
* fixing receipt id generation (https://github.com/jasonrbriggs/stomp.py/pull/102)
* generate disconnect receipt ids (https://github.com/jasonrbriggs/stomp.py/pull/108)
* don't send unnecessary heartbeats (https://github.com/jasonrbriggs/stomp.py/pull/113)
* fix misdetection of heartbeats (https://github.com/jasonrbriggs/stomp.py/pull/120)
* Merge patch from Hugh P, adding SNI support (https://github.com/jasonrbriggs/stomp.py/pull/124)
* Fix for heartbeat calculation error (https://github.com/jasonrbriggs/stomp.py/pull/125)