Update main.py

added speed control (f for faster, s for slower, increments by one and limited to a 1 to 30 range setting default speed to 30...this range encompasses really the only "meaningful" speeds)

could add a "skip" factor later if you wanted to go faster by simply skipping display of generations
Update life.py
Update life.py
Merge pull request #5 from c4ts4thewin/t-addspeed-control

T addspeed control