Merge pull request #119 from mattycourtney/master

Fixes gocardless/hutch#116 by replacing :ack with :manual_ack
Document `:publisher_confirms` and `:force_publisher_confirms`
Sync with upstream
Bunny 1.6.1+
Typo
Introduce Hutch.disconnect
Log it when publisher confirms are enabled
Gotta use #[] here
Introduce Hutch::Config.to_hash, which is more obvious than .user_config
Back to dev version
Make it more obvious how to force publisher confirms
New iteration section