Adds a menu item to the appearance menu, "clean up project morphs". When selected the project morphs are sorted alphabetically and placed as if on a grid, evenly spaced. A preference controls whether the project thumbnails are created horizontally or vertically. The spacing is determined by the way it finds the first morph in the World. The amount of margin it is currently using, and it's size, is used to resize and position the other project thumbnails. See http://squeak.preeminent.org/ for a picture