Version 0.8.0: UI Updates and Improvements

This version includes a number of UI improvements and quality of life changes. These are designed to make the game look better and make it easier to navigate (especially between different levels).

• Introduced a new level select modal which shows a preview of each level before you select it.
• Improved the level layout, replacing plain white backgrounds and moving some buttons and UI elements to the top of the screen.
• Removed numbered axis labels and replaced them with a cleaner level border.
• Improved responsive design for smaller screen sizes.
• Updated relevant tutorial GIFs to reflect the new UI changes.
• Change step counter to start at 0 instead of 1 (issue #89).
• Minor tweak to make it more clear how code length is counted for certain bonus challenges.