Comprehensive HTTP Router

Here is a partial solution to Issue #202, at least for different HTTP methods.  There is no provision for websocket or SSE support here.  This is more or less a port of the excellent Vert.x RouteMatcher for RxNetty.  I do want to point out that I had to force queryParameters to be mutable on HttpRequest for this particular implementation.
I would like to keep the code consistent and not use a mix of groovy and java. Any specific reason you want to use groovy here?