Changed to correct WOQL AST keyword (fixes #312)

Author: hoijnet

lib/query/woqlQuery.js

@@ -604,7 +604,7 @@ WOQLQuery.prototype.removed_quad = function (subject, predicate, object, graphRe
   // if (a && a === 'args')
   // return args.concat(['graph'])
   if (!graphRef) return this.parameterError('Quad takes four parameters, the last should be a graph filter');
-  this.cursor['@type'] = 'RemovedQuad';
+  this.cursor['@type'] = 'DeletedQuad';
   this.cursor.graph = this.cleanGraph(graphRef);
   return this;
 };