optional tls_ctx arg.

This is the only action that makes sense, AFAIK there are no users of
this code that are not already working around this issue.

Issue #71.

- Switch from distribute to setuptools
- Tweak compilation on MacOSX to use homebrew openssl
- Use MANIFEST.in to include files needed to build

frob: wrap hex-encoded binary data with '<>'.

Issue #70.

# Please enter a commit message to explain why this merge is necessary,
This merge is necessary because I forgot to pull, AGAIN.

url: to shrapnel.
version: raised from 0.5 to 0.8.

This code has been copied with permission from:
    https://github.com/samrushing/amqp-shrapnel
It also has been changed to pass pep8 and to work in the
coro package.

most APPLICATION need STRUCTURED.
ReadyQueue: rather than yield/schedule, which is error-prone.
search: handle multiple-entry replies.
unbind: close like a pro.
use module-level logging.

Fixes #65

untested.
[need to find/write a test suite for this, dunno where the old one went].