websocket: Fix case where incorrect signed gsize was used in test
websocket: Don't complain if older hixie clients skip close handshake

The first websocket protocol 'spec' allows this, and in fact
phantomjs 1.9 doesn't send a closing handshake.

http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-75#page-31

Fixes #114