Proposed Release 1.13

Require Net::AMQP 0.06 to:
get consume cancel notifications (e.g. queue deletion);
  properly encode user-provided header strings that look like numbers.
Fix race between server-sent and client-sent cancellation.
Expect server to send heartbeats as promised.  If it doesn't, go President
  Madagasgar on its ass and SHUT DOWN EVERYTHING.
Rearrangeme many things and weaken many references to eliminate bad circular
  references.  Some circular refs are actually good, though; leave those.
Allow customized client_properties on connection.
Make test output clearer.