Introduce Elasticsearch YARN project

Relates #321
Significantly improve compatibility across YARN versions

Since the API between Hadoop versions is not backwards compatible,
expand the compat layer to allow the binary to run across 2.2, 2.3,
2.4, 2.4.1, 2.5 and 2.5.1. Note the latest 2.4 (2.4.1) is recommended.
Additionally add plenty of polishing to the CLI

related to #321
Remove unused configuration options
Improve bug occurring with slow container allocation
More polishing
Allow cfg files plus variables to be specified through the CLI

Improve env setup for spawned containers
[DOCS] Add docs on YARN

relates #321
[DOC] Crop container list image
temporarely disable YARN tests for the CI
[DOC] Properly crop image
Add handling of date inside WritableValueReader

Fix #320
Fix typo

Fix #318
[DOC] Fix typo

Fix #301
Update README.md

Fixing typo in maven dependency
Closes #314
Signed-off-by: Costin Leau <costin.leau@gmail.com>
[SPARK] Support rich mappings

Allow rich/complex mappings in SparkSQL
[DOC] release updates + upgrade to ES 1.4
Release 2.1.0.Beta3
Next dev version
Merge remote-tracking branch 'upstream/master'