Align extended Boolean parsing with Elasticsearch

[jbaiera]

As it stands, the boolean parsing in ES-Hadoop checks for values true, on, yes, and 1, with all other values being false. Elasticsearch defines it's logic as false, off, no, and 0, with all other values being true.

This means the ES-Hadoop is biased towards parsing booleans as false, whereas Elasticsearch is biased towards parsing booleans as true. For instance, if a field is mapped as a boolean, and a document with the value "blah" is indexed, in Elasticsearch, this would be treated as a true value, whereas in ES-Hadoop's extended boolean parsing, we would treat this as a false value.

[jbaiera]

Additionally, Elasticsearch will directly treat any numeric field as a potential boolean, with any floating point values coerced to integral types and all non zero integral values being true and all zero integral values being false.

This is handled outside of the Booleans class in Elasticsearch core, and so it will be left out of this issue and is fixed with issue #795 .