If listening on some local addresses fails for multicast requests, only a warning is printed out without stack trace. Fixes #135
Merge branch 'master' into 2.0

Conflicts:
	agent/core/src/main/java/org/jolokia/discovery/DiscoveryMulticastResponder.java
	agent/jvm/src/main/java/org/jolokia/jvmagent/JolokiaHttpHandler.java
	service/discovery/src/main/java/org/jolokia/service/discovery/MulticastSocketListenerThread.java