Add new theme

configure

configure.in

themes/Makefile.am

themes/Makefile.in

themes/slick/Makefile.am

themes/slick/Makefile.in

themes/slick/bottom-active.xpm

themes/slick/bottom-inactive.xpm

themes/slick/bottom-left-active.xpm

themes/slick/bottom-left-inactive.xpm

themes/slick/bottom-right-active.xpm

themes/slick/bottom-right-inactive.xpm

themes/slick/close-active.xpm

themes/slick/close-inactive.xpm

themes/slick/close-pressed.xpm

themes/slick/hide-active.xpm

themes/slick/hide-inactive.xpm

themes/slick/hide-pressed.xpm

themes/slick/left-active.xpm

themes/slick/left-inactive.xpm