Add JSON OutputFormat with embedded MarkLogic JSON triples

[masyukun]

Example:

{
  "my": "data",
  "rtTriples": [
    {
      "triple": {
        "subject": {
          "value": "771321013"
        },
        "predicate": {
          "value": "hasRating"
        },
        "object": {
          "datatype": "http:\/\/www.w3.org\/2001\/XMLSchema#string",
          "value": "R"
        }
      }
    },
    {
      "triple": {
        "subject": {
          "value": "2015-02-27"
        },
        "predicate": {
          "value": "hasReleaseDate"
        },
        "object": {
          "datatype": "http:\/\/www.w3.org\/2001\/XMLSchema#string",
          "value": "March 15"
        }
      }
    }
  ]
}