Platform-independent navigation is available now. New script result called ScriptResultType.Navigation is introduced. To perform navigation scriptwriter should use the following call: 

            ScriptContext.Result = Navigator.UrlFor(target);
            ScriptContext.ResultType = ScriptResultType.Navigation;

where as 'target' possible values are Item, SmartList, Workspace, List objects.  Navigator.UrlFor is used to navigate to object's page itself, e.g item details, list page or workspace summary.