Memory Visual support?

[Eric , Yu-En Lue]

Hihi
        I read the manual , it uses "display-visual" when opening
        the memory visual , however , in ggi_init , I see only
        string like "memory" , which one should I use? :)

        And is there any constriants or differences using the
        ggi-frame-buffer visual and the memory one?

        thanks!