ISPN-4225 Upgrade to JGroups 3.5.0.Beta5
ISPN-4190 Use Message.Flag.DONT_LOOPBACK instead of RequestOptions.setExclusionList

DONT_LOOPBACK is now a transient flag
ISPN-1951 Use MERGE3 in the default UDP configuration

TEST_PING needed some changes, as MERGE3 doesn't trigger Discovery.findMembers()
Smaller timer pool and queue.
Still causes lots of failures.