#6 Sprites disappear when ambient lighting level changes

[Delano]

Sprites become invisible (but are still active) when the ambient lighting level changes, either through an RPGCode program or when moving to a board with different ambient lighting conditions. To reproduce:

1. Create a program on a board containing the code: setAmbientLevel(32, 32, 32);
2. Place an item on the board.
3. Set as the starting board and run the game.
4. Trigger the program by walking the player over it. The player and the item disappear. The player can still be controlled by the user (e.g. it can trigger other programs and move to other boards).

Version = 3.1.0