Map tiles graphical refactoring

[Adrian-Moldovan]

• [x] The tile indexes should be commented. Don't delete the code, as we might use the info for debugging
• [ ] Investigate creating smaller map tiles. Check if information remains clear.
• [x] As the tile yield becomes positive, the displayed yield icon (clover or mushroom) must be changed. I suggest keeping the clover icon and eliminate the mushroom.
• [x] Optional: the tile yield color should reflect the score value (and in the future, the question difficulty). Use the color scheme from the player energy level.

[RaresGherasim]

Partialy finished.