Major demo update!

Improved or added:

1. Interaction menu for Little Lieris.

2. New attacks for the boss in the Storm Tower.

3. The unicorn can cast purple lightning near the player.

4. Items now float smoothly into the bag.

5. Auto-save for dropped items has been improved.

6. You can now have a snowball fight with Little Lieris.

7. Scene loading optimizations.

8. The Shadow Pegasus now flies off suddenly when attacking, rather than simply standing still.