ISPN-4419 Upgrade to netty 4.0.20.Final and use provided DefaultThreadFactory for max perf
ISPN-4420 Allow configuring keepalive for hotrod connections
ISPN-4396 DSL Query right condition lost

The right condition of an OR or AND subcondition nested inside an outer NOT condition is lost because BaseQueryBuilder.not(FilterConditionContext fcc)
does not properly determine the root of the nested subcondition.
ISPN-4420 Allow configuring keepalive for hotrod connections
- fixed test
ISPN-4112 RHQ library plugin: restart cache -- availability report DOWN
but cache running

* Added back in availibilty down for cache not running
* Added server changes to also report DOWN when cache not running
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.