ISPN-4690 Upgrade to Scala 2.11.2

* Minor compilation adjutsments were required, including: switching
to new scala.concurrent classes added in 2.10, extend Serializable
trait instead of annotation, and use refactored Java conversion
methods.
* Scala XML module has been separated, so REST server needs a new
dependency, which it has also been added to Infinispan server as
a new module.
Replace sfl4j-jdk14 dependency with sfl4j-log4j12 so that jboss logging
writes to log4j in the cdi module (and dependents).

Add more debugging around cache listeners. It seems Class.getMethods()
sometimes returns synthetic methods created by overriding a generic method.