ISPN-4505 Lucene Directory polishing
ISPN-4505 Now using @Override for methods which couldn't be marked properly before
ISPN-4505 Document the fact we dropped compatibility with older Lucene versions
ISPN-4278 Add QOP support to the HotRod SASL implementation
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.