Initial OXO code

Signed-off-by: Paul Brook <paul@nowt.org>
Artificial stupidity

Signed-off-by: Paul Brook <paul@nowt.org>
Fix diagonal generation

Signed-off-by: Paul Brook <paul@nowt.org>
Fix game logic.  Automatic AI.

Signed-off-by: Paul Brook <paul@nowt.org>
Make AI smarter

Signed-off-by: Paul Brook <paul@nowt.org>
Merge branch 'oxo'