Part 2: Made changes according to Michael's suggestions

Made remaining stylistic improvements.
Used enum instead of int for board and lastMove
Part 3: Made changes according to Michael's suggestions

Used casin conventional to Vala.
Added simple check for vertical wins.

This commit has plenty of debugging messages.
Committing it only to save progress so far.
A few major TODO's left. Game not fit for playing
in this commit.
Added horizontal and diagonal win cases.

Again, code has lots of debugging code as well.
Commiting to store progress.
Added a small change to quash more recent threats first.

Again, a lot of debugging info present.
Removed all debugging messages

This commit should have a version of AI that
correctly checks for wins and losses.
Game should now work fine on reload

Added a board_reset method that gets
called on reload_game. Fixed another issue
being caused by NEG_INF not being small
enough.
Always use a space before an opening parenthesis
Convert all tabs to spaces
Add a modeline
Add a copyright notice