UPDATE: Hotkey previews, improved videos, solitaire tweaks

Today's update includes the following changes:

• Added previews when placing instructions using hotkeys.

• Improved the color accuracy of MP4 files exported using ffmpeg.

• Tweaked the ippatsu-dai variant of pachi-sol so that it's slightly easier to win.

• Adjusted the "spring dress" puzzle so that the lower fabric can be flipped vertically.

• Adjusted the "katsu curry" puzzle so that it's more obvious when assembled incorrectly.