Added TicTacToe in Samples

Here's just one more sample — a tic tac toe game! 

It runs easily with `jruby -J-XstartOnFirstThread shoes4/bin/ruby-shoes shoes4/samples/simple-tictactoe.rb`.
The three preceding lines could be expressed by just `all_checked?(diagonal1) || all_checked?(diagonal2)`. Typical Ruby style tries to avoid `return`s by ending with the value we want returned, and this case lets us do that nicely.

Along those lines, the `(1..3)....` could be reframed as the following to `||` with the later conditions, but I'm not sure whether I buy that it's much clearer:

```
(1..3).any? { |i| all_checked?(row(i)) || all_checked(column(i)) }
```