Upstream Elasticsearch does not support embedded nodes as of
Elasticsearch 5. This commit removes the usage of embedded nodes within
YCSB.

This commit adds notes to the Elasticsearch documentation outlining the
difference between embedded and remote modes, and adds an example on
using remote mode.

This commit fixes the Elasticsearch name in the README file for the
Elasticsearch project from "ElasticSearch" to "Elasticsearch".

Bumped elasticsearch version and fix multiple api changes.
update README.md troubleshoot section.