Add age to cell state

[modul]

Instead of 4 states to track Birth, Survival, Dying and Death, the cell age holds the same information while keeping the two important states Alive and Dead:

`data Life = Alive Int | Dead Int;

rule (Alive age) 2 = Alive (age + 1)
rule (Alive age) 3 = Alive (age +1)
rule (Alive _) _ = Dead 0
rule (Dead age) 3 = Alive 0
rule (Dead age) _ = Dead (age + 1)`