Menubar window resize fix

[tuttza]

I think I found the issue(and a fix!) that was causing windows not to be able to shrink after making the window larger with Menus enabled.

The culprit resides in gtk.c essentially we were incorrectly referencing the widget pointer.

before:

    GtkWidget *wdg = app->slot->oscanvas;
    gtk_widget_set_size_request(wdg, app->width, app->height);

after:

    GtkWidget *wdg = app->slot->oscanvas;
    gtk_widget_set_size_request(&wdg, app->width, app->height);

Also I added some braces around if statements (which is really most of the other changes). I think we should start doing that seems to be a good practice follow.

[ccoupe]

Sadly there are problems.

1. The scrollbar resizing is incorrect - try the manual with menus enabled to see it. There is a history of these two bugs in an xor relationship.
2. I get a long line(s?) of garbage on my linux launch terminal when Shoes exits.

Reference #430