o draw viewport bg using base colors from style
    o set Layout box border width and spacing

  * gladeui/glade-design-layout.c:
    o removed padding (now set on parent)
    o added PangoLayout to draw widget name
    o added space needed for widget name in glade_design_layout_get_preferred_height ()
    o glade_design_layout_size_allocate() allocate enough space for widget name
    o moved widget name to south east and used as resize grip
    o update widget name on GladeWidget::notify:name