Happy New Year! I've updated the desktop versions of Otteretto with some major upgrades, particularly for Puzzle mode.

Patch notes:

- Reworked puzzle generator for more consistent difficulty
- Added progress saving for Puzzle mode
- Added the ability to give up and view the solution for a puzzle
- Save games are now per-mode, and you can return to the modes menu with a game in progress
- The game now remembers its window size and full screen state, and restores it when relaunched
- Global high score pages now default to showing monthly leaderboards (all-time scores are still visible on the website)
- Fixed some achievements that were not correctly triggering in certain scenarios