Bring extension up-to-date with new API.

git-svn-id: http://svg-edit.googlecode.com/svn/trunk@1458 eee81c28-f429-11dd-99c0-75d572ba1ddd

editor/extensions/ext-helloworld.js

@@ -13,8 +13,7 @@
  	user the point on the canvas that was clicked on.
 */
  
-$(function() {
-	svgCanvas.addExtension("Hello World", function() {
+svgEditor.addExtension("Hello World", function() {
 
 		return {
 			name: "Hello World",
@@ -75,6 +74,5 @@ $(function() {
 				}
 			}
 		};
-	});
 });