make sure http response header charset=UTF-8

Currently http://localhost:8080/designer/?locale=ja responds with http header charset=ISO-8859-1 so FireFox opens the page with Windows-1252(ISO-8859-1) and some Unicode characters are garbled. (<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> doesn't help this problem)

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
X-Powered-By: JSP/2.2
Content-Type: text/html;charset=ISO-8859-1
Transfer-Encoding: chunked
Date: Wed, 03 Jul 2013 07:29:30 GMT

Two fixes to make sure http response header charset=UTF-8.

1) JSP requires <%@ page contentType="text/html;charset=UTF-8" %>  because default is ISO-8859-1.

2) Moved response.getWriter() after chain.doFilter() because getWriter() fixes characterEncoding and subsequent response.setCharacterEncoding("UTF-8") will have no effect (e.g. in UberfireServlet.doGet())