Custom registration of listeners

[johnament]

Right now, in each of Undertow, Jetty and Tomcat, the listener class is manually registered. E.g.

//  Tomcat
ctx.addApplicationListener(Listener.class.getName());

// Jetty
context.addEventListener(new Listener());

// Undertow
.addListener(listener(Listener.class));

In two, they're class references and in jetty its the actual instance reference. Need to somehow generify this to work not specific to weld.

[johnament]

This was done in another ticket, #62