TermsExecution should have additional value: "or", "fielddata"

[dqduc]

As ES document http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-terms-filter.html

The correct TermsExcution enum should be:

public enum TermsExecution
  {
   plain,
   @bool,
   and,
   or,
   fielddata
  }