Capture processHandshake error

[bbangert]

processHandshake does not handle headers happily when a unicode error occurs. We should capture this better since our override calls the main one.

UnicodeEncodeError: 'ascii' codec can't encode character u'\xe5' in position 9: ordinal not in range(128)
  File "autopush/websocket.py", line 111, in wrapper
    return func(self, *args, **kwargs)
  File "autopush/websocket.py", line 383, in processHandshake
    return self.parent_class.processHandshake(self)
  File "autobahn/websocket/protocol.py", line 2552, in processHandshake
    protocols = [str(x.strip()) for x in self.http_headers["sec-websocket-protocol"].split(",")]

[bbangert]

And:

UnicodeEncodeError: 'ascii' codec can't encode character u'\xf8' in position 93: ordinal not in range(128)
  File "autopush/websocket.py", line 111, in wrapper
    return func(self, *args, **kwargs)
  File "autopush/websocket.py", line 383, in processHandshake
    return self.parent_class.processHandshake(self)
  File "autobahn/websocket/protocol.py", line 2519, in processHandshake
    return self.failHandshake("HTTP Connection headers do not include 'upgrade' value (case-insensitive) : %s" % self.http_headers["connection"])
  File "autobahn/websocket/protocol.py", line 2861, in failHandshake
    self.sendHttpErrorResponse(code, reason, responseHeaders)
  File "autobahn/websocket/protocol.py", line 2868, in sendHttpErrorResponse
    response = "HTTP/1.1 {0} {1}\x0d\x0a".format(code, reason)