Post jam update

Here comes a small but much needed post jam update consisting of around ~4 hours of additional work.

Patchnotes:

• Added smoothing to the shovel following the cursor
• Added a digging animation with a treasure chest appearing on hit
• Changed max timer time from 10 -> 12 seconds
• Added a alert when there is 3 seconds left
• Added a local highscore
• Changed algorithm for calculating time rewards for each treasure found, hopefully making for a more balanced experience.
• Improved map visuals
• Improved timer visuals
• Improved game over screen
• Fixed player being able to continue playing after game over
• Fixed the X sometimes spawning outside the play area