added XML escape method.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@3146 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Functions.java

@@ -347,6 +347,10 @@ public class Functions {
         return Util.escape(s);
     }
 
+    public static String xmlEscape(String s) {
+        return Util.xmlEscape(s);
+    }
+
     public static void adminCheck(StaplerRequest req, StaplerResponse rsp, Object required) throws IOException, ServletException {
         if(required!=null && !Hudson.adminCheck(req,rsp)) {
             // check failed