title: method cursor in trait GenericQueryBuilder is deprecated
body: <p>I'm working with <code>"org.reactivemongo" %% "play2-reactivemongo" % "0.11.7.play24"</code> and when i compile my proyect, show me the next errors:</p>
  
  <pre><code>[error] /home/hector/enova/play-silhouette-reactivemongo-seed-master/app/controllers/CourseController.scala:90: method cursor in trait GenericQueryBuilder is deprecated: Use [[cursor]] function with read preference.
  [error]       cursor[JsObject]
  [error]       ^
  [error] /home/hector/enova/play-silhouette-reactivemongo-seed-master/app/controllers/CourseController.scala:120: method cursor in trait GenericQueryBuilder is deprecated: Use [[cursor]] function with read preference.
  [error]       cursor[JsObject]
  [error]       ^
  [error] two errors found
  [error] (compile:compileIncremental) Compilation failed
  </code></pre>
  
  <p>The lines 90 and 120 are are in bold:</p>
  
  <pre><code>    val cursor: Cursor[JsObject] = collection.
        find(Json.obj("title" -&gt; title)).
        sort(Json.obj("created" -&gt; -1)).       
        cursor[JsObject]
  
  
      val cursor: Cursor[JsObject] = collection.
        find(Json.obj("active" -&gt; true)).
        cursor[JsObject]
  </code></pre>
  
  <p>How can i fix this?</p>