Character can only eat smaller fishes

[9728627]

This should be a new feature. The fishes which have larger sizes should not be eaten by characters. Characters can only eat fishes that have smaller sizes. It should be very cool.

200xp

[xavierholt]

This is now combined with the (closed) #101. There are two main parts that play against each other:

• As the shark eats more fish, it grows bigger.
• The shark can only eat fish that are smaller than itself.
• Possibly: Really big fish can eat the shark!

F17 OK: 400 XP

[aryamandas]

W18 OK (400 points)