Enable sending a one off binary message.

Also, for the autobahn test program, close after initial pong.
Enable sending binary pong.
Get rid of CLang warning about implicit type conversion.
Make sure we empty the entire buffer when reading websocket data.

This fixes a bug that caused unclean close for some autobahn tests.
Don't close with incorrect status.

Still some fixing to do...
Some todos.
Don't close explicitly after pong (the server does it).