Sort Them All

How to play?
- Goal of the game is to sort out all the colors
- To pour the top liquid layer, first click on the source tube then on the target tube

Note:
- Costumes are dynamical based on the contents (various mixing of colored liquids)
- Pouring is manipulating the internal variable contents
- Variables are shared by cloning, therfore a deep copy with ID is needed.

Next:
- Optimize for an unified way of list access
- Some pouring animation