- it's available natively since IE8 and it's provided by Chrome Frame which is a requirement for old IE
- it's only used for postMessage exchange which is a newer API than JSON
- if ever we would need it, it should be added in an external lib, not inside the editor code itself
git-svn-id: http://svg-edit.googlecode.com/svn/trunk@2462 eee81c28-f429-11dd-99c0-75d572ba1ddd