Big pattern added

Now when you load Main.hs and type `main', vacuum-cleaner pattern will
be used be default.

But this is a complex and big (ca. 100x100) pattern and GHCi
(interactive) needs about 0.5 sec to compute the next step.

The good news is that if you compile the program

ghc --make Main.hs

you can easily have eight steps per second, perhaps even more.

Our Game of Life is now truly alive!