put websockets in blocking mode when writing

We were encountering a OpenSSL.SSL.WantWriteError on
arbor.kitware.com when attempting to send a relatively large
image to the client over wss.  This change solves the problem.
Merge branch 'wss_timeout' of github.com:zackgalbreath/tangelo into zackgalbreath-wss_timeout
Added a comment marking the change to upstream ws4py
Merge branch 'zackgalbreath-wss_timeout'