Update default theme

themes/default/bottom-active.png

themes/default/bottom-active.svg

themes/default/bottom-active.xpm

themes/default/bottom-inactive.png

themes/default/bottom-inactive.svg

themes/default/bottom-inactive.xpm

themes/default/bottom-left-active.xpm

themes/default/bottom-left-inactive.xpm

themes/default/bottom-right-active.xpm

themes/default/bottom-right-inactive.xpm

themes/default/close-active.png

themes/default/close-active.svg

themes/default/close-active.xpm

themes/default/close-inactive.png

themes/default/close-inactive.svg

themes/default/close-inactive.xpm

themes/default/close-prelight.png

themes/default/close-prelight.svg

themes/default/close-prelight.xpm

themes/default/close-pressed.png