Add missing Id keywords to input_choice.
Add sudoku to demo program.
Add on-line help to sudoku game, and put all of the cells in the main
window so that the keyboard navigation is sane.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@4659 ea41ed52-d2ee-0310-a9c1-e6b18d33e121