com.x10clab.jaring.Jaring: add method getRequestBodyJson.

This method is used to retrieve request body as a single JSONArray.
js.jaring: update frameworks.

* Jx.GridPaging:
  - add option to automatically create row editor.

* Jx.StorePaging:
  - add writer configuration.
  - default autoDestroy is true.

* Ext.data.Store.renderData: method to render store in column.
SystemMenu: update interface.