version 0.0.12

Refactoring to use packet Queues unearthed many new difficulties, so
here's a bunch of changes all at once. I got rid of the protocol channel
as its own subclass, since that turned out to be more a question of
"consumer of channel" versus "nature of channel" after all.
version 0.0.12 (alpha) ready for PyPI
pep8 cleanup