SloppyMath

Added copy of SloppyMath.java from lucene 4.6+
and setup GeoDistance for new haversin method

closes #3862
introduce an internal metadata uuid
Make listeners a final field in ShardIndexingService, which fixed possible visibility issue.
Simplify nodes stats API

First, this breaks backwards compatibility!

* Removed /_cluster/nodes/stats endpoint
* Excpect the stats types not as parameters, but as part of the URL
* Returning all indices stats by default, returning all nodes stats by default
* Supporting groups & types in nodes stats now as well
* Updated documentation & tests accordingly

Closes #4057
Allow to set "level" parameter to "shards" and "indices"

"cluster" does not make a lot of sense in nodes stats

TODO: Squash with the other commit after review