9x9 puzzles

The puzzle generator built into the app can now generate 9x9 puzzles! This is the main change in version 1.45.0. All the changes in detail:

• The Advanced and Expert modes of Random Play now support generation of 9x9 puzzles. 9x9 puzzles can also be launched from any play mode when the option to select the size of the next puzzle is enabled in the Random Play settings. The free preview of Random Play has been supplemented with some examples of 9x9 puzzles.
• When puzzles are generated with hidden sum values, the difficulty weighting selected in the settings is now observed more closely.
• Empty squares have a slightly darker appearance than squares with numbers. This gives a clearer distinction between squares where it is known that a number will appear and squares where a block might still be possible. It also helps to make pencil mode easier to use.
• A new app setting makes it possible to disable Game Center completely. The app settings can be found in the section Sumaddle of the device settings.
• The screens for the in-app settings have been de-cluttered by moving additional information into info items which are collapsed by default.
• More improvements to help explanations.