NoClassDefFoundError using RadiusClient without bouncycastle

[dub357]

The RadiusClient.registerAuthenticator method can potentially throw a java.lang.NoClassDefFoundError (subclass of java.lang.LinkageError) if the extended classes (jradius-extended.jar) are in the classpath, but the bouncycastle provider isn't, therefore making the RadiusClient unusable since the "registerAuthenticator(String, String)" methods are called statically but only with a catch block for ClassNotFoundException.