added zharks & (mutated) zalmons, removed zfish...
return nearby fish function added
1. added and refined zfish & their spawn chances
2. made the flag FISH useable (and declared it)
3. created the get_fishable function that returns the fish in a 60-wide area
4. made the fish trap code fish from the fishes around
fixes so that the whole thing up to now compiles and works as intended.