Update to elasticsearch 1.4.0

Closes #24.
(cherry picked from commit e03a16b)

README.md

@@ -6,6 +6,7 @@ The JavaScript language plugin allows to have `javascript` (or `js`) as the lang
 In order to install the plugin, simply run: `bin/plugin -install elasticsearch/elasticsearch-lang-javascript/2.1.0`.
 
 * For master elasticsearch versions, look at [master branch](https://github.com/elasticsearch/elasticsearch-lang-javascript/tree/master).
+* For 1.4.x elasticsearch versions, look at [es-1.4 branch](https://github.com/elasticsearch/elasticsearch-lang-javascript/tree/es-1.4).
 * For 1.3.x elasticsearch versions, look at [es-1.3 branch](https://github.com/elasticsearch/elasticsearch-lang-javascript/tree/es-1.3).
 * For 1.2.x elasticsearch versions, look at [es-1.2 branch](https://github.com/elasticsearch/elasticsearch-lang-javascript/tree/es-1.2).
 * For 1.1.x elasticsearch versions, look at [es-1.1 branch](https://github.com/elasticsearch/elasticsearch-lang-javascript/tree/es-1.1).

src/main/java/org/elasticsearch/script/javascript/JavaScriptScriptEngineService.java

@@ -234,11 +234,6 @@ public void setNextDocId(int doc) {
             lookup.setNextDocId(doc);
         }
 
-        @Override
-        public void setNextScore(float score) {
-            ScriptableObject.putProperty(scope, "_score", score);
-        }
-
         @Override
         public void setNextVar(String name, Object value) {
             ScriptableObject.putProperty(scope, name, value);