* Changing the Save/Load text to a floppy-disc icon (and making it slightly smaller than the other options).
* Generalising the main widgets to all use the same super-class (to make it easier to add things later).
* Fixing a typo that meant that the sudoku puzzles were saving to the crossword save file. (This wouldn't have been noticeable on the user side, but I wanted to fix it anyway. If you had saved any sudoku puzzles since I added the option 2 days ago: Sorry, but you're going to lose your saved Sudokus!)
