Move wallis to separate theme package.

themes/wallis/Makefile.am

themes/wallis/README

themes/wallis/bottom-active.png

themes/wallis/bottom-active.xpm

themes/wallis/bottom-inactive.png

themes/wallis/bottom-inactive.xpm

themes/wallis/bottom-left-active.png

themes/wallis/bottom-left-active.xpm

themes/wallis/bottom-left-inactive.png

themes/wallis/bottom-left-inactive.xpm

themes/wallis/bottom-right-active.png

themes/wallis/bottom-right-active.xpm

themes/wallis/bottom-right-inactive.png

themes/wallis/bottom-right-inactive.xpm

themes/wallis/close-active.png

themes/wallis/close-active.xpm

themes/wallis/close-inactive.png

themes/wallis/close-inactive.xpm

themes/wallis/close-pressed.png

themes/wallis/close-pressed.xpm