Add struts2demo: MethodFilterInterceptor.
Add struts2demo: fileupload.
Add struts2demo: download file.
Add struts2demo:download file with filename & resolve charset problem.
Add struts2demo: resolve charset problem.
Add struts2demo: annotation.
Add struts2demo: ajax.
Add struts2demo: json datatype.
Add struts2demo: get container object.