- Use prctl to set the lwp/thread name under Linux. This makes the
  threads easily identifiable in top.
copy any 'data' directories to the root of the flatjar. Fixes LOGSTASH-715, LOGSTASH-851
- Set input thread names to "<" followed by the plugin name
- Set output thread names to ">" followed by the plugin name
- Set filter worker threads names to "|" followed by "worker.N" where N
  is the worker number.
- add note about thread names
- don't reference "?local" anymore since it's obsolete
- update tutorials to use new date 'match' syntax instead of the older
  deprecated one