Change default theme

themes/default/close-active.xpm

themes/default/close-inactive.xpm

themes/default/close-pressed.xpm

themes/default/hide-active.xpm

themes/default/hide-inactive.xpm

themes/default/hide-pressed.xpm

themes/default/maximize-active.xpm

themes/default/maximize-inactive.xpm

themes/default/maximize-pressed.xpm

themes/default/maximize-toggled-active.xpm

themes/default/maximize-toggled-inactive.xpm

themes/default/maximize-toggled-pressed.xpm

themes/default/menu-active.xpm

themes/default/menu-inactive.xpm

themes/default/menu-pressed.xpm

themes/default/shade-active.xpm

themes/default/shade-inactive.xpm

themes/default/shade-pressed.xpm

themes/default/shade-toggled-active.xpm

themes/default/shade-toggled-inactive.xpm