Add a system property to redirect jboss logs to slf4j

[stevehu]

As Undertow is using jboss logging and we are using slf4j with logback in our framework, we cannot see any log from Undertow even errors. In order to make Undertow use our slf4j and logback config, we need to add a system property in the command line or just add a line in Server.java.

I think the second option is much better as we always need it.

        System.setProperty("org.jboss.logging.provider", "slf4j");

In order to capture all the exceptions in ExceptionHandler, dispatch in the exception handler as suggested by Bill O'Neil.