Fix paper-bag bug in heartbeat - always lost heartbeat even on active connections
on channel close, automatically call on_return callbacks for any publishes that are waiting
pass frame to publish on_ack and on_nack callbacks, because why not
on_return is called in *addition* to on_ack/on_nack
document ->publish
update docs for remaining branch changes
don't immediately recycle channel ids; this helps avoid protocol misunderstandings
harden channel close against races; obey spec: ignore all incoming packets after sending Close
use Devel::GlobalDestruction to protect Channel
use Devel::GlobalDestruction to protect connection
implement full state machine around connection closing
add doc for close state fixes
Version 1.14