ioworker: Add first pass at shutdown() method
ioworker: Hack around constructor problem

Really, the RecocoIOWorker base class constructor shouldn't take a socket.
ioworker: Fix server worker _do_accept param reversal
ioworker: Fix _do_accept() exception in server workers

Looks like I accidentally removed a line.  Oops.
ioworker: Allow listener socket reuse

It's possible that this should be an option.
ioworker: Handle async sockets on Windows

Another attempt to address #67.
of_01: Handle read exceptions