Puzzle generator improvements

Version 1.48.0 includes improvements to the built-in puzzle generator and other small enhancements. The changes in detail:

• New logic has been added to the Random Play puzzle generator. This makes it possible for puzzles generated in Expert play mode to be harder than ever!
• Improvements to the way the difficulty rating is estimated for puzzles generated by the puzzle generator in Random Play.
• When the help is used to fix mistakes and the option to clear the puzzle is selected, an “are you sure?” popup is now shown. This is to help prevent the puzzle from being cleared accidentally.
• Items in a popup menu are easier to select: blank space next to an item is also sensitive to tapping.
• A fix for the wrong list of leaderboard entries sometimes being shown when switching between the current and previous Random Play leaderboards around the time of the daily leaderboard reset.
• A fix for double-tap value elimination when used on the last free square of a multiple selection. Previously, double-tap wasn’t working in this case.
• Improvements to help explanations.