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`.
Rather than a `select` + `each` + `<<`, you can just take the result of `select and add it into `tics.

```
  tics.concat(@tics.select { |tic| ... })
```

You may need to `flatten` the `tics` at the end, but it'll end up a bit tidier that way.