ROO-3444:  Improve method level security of Spring Roo services

    Improve method level security of Spring Roo services by including a 
    PermissionEvaluator.

    To use this functionality, first create a Permission Evaluator
    using the permissionEvaluator command.  Then, to any service
    that should use a permissionEvalutator, set the @RooService
    usePermissionEvaluator attribute to true.

    Roo will add/modify the @PreAuthorize annotations to saveOrUpdate
    and delete.  It will add @PostAuthorize to find.  The default permission
    evaluator logic is very basic.  It simply returns
    false or true depending on the default value.  Users should
    replace the appropriate methods to get the desired behvior.