[Vala] Signals for GType fundanmental classes.

[Yu Feng <rainwoodman gmail com>]

http://bugzilla.gnome.org/show_bug.cgi?id=561989

test case:

class AAA {

    public AAA() {

    }
    public signal void changed();
    public void change() {
        changed();
    }
    public static int main(string[] args) {
        AAA aaa = new AAA();

        aaa.changed+= (o) => {
            message("hello");
        };
        aaa.change();
        return 0;
    }
}


Regards,

Yu