1.5.13: Fix websockets functionality for Ignition 8.1.25+

This version applies one more fix to those from #32 related to how the websocket channel is setup. With Jetty 9, we called both a register and a setCreator method in order to configure the websocket creation. With Jetty 10, invoking that register method seems to take precedence over our prescribed creator and drive use of a no-arg constructor for the class instead. Removing that register call is all that is needed.