[Delivers #62121438] Take corner on first move.
[Delivers #62122922] Second move strategy.

If previous move was center, play corner.
Else, player center.
Rake task to build commits since last push.
Simplify class names for FirstMove and SecondMove.
[Delivers #62149404] Fork strategy.

Identify positions which create two threats for
opponent.
[Delivers #62152590] Block Fork Strategy.

If opponent is able to fork in next move, force
opponent to block a position that will not create
fork.
[Delivers #62152828] Opposite corner strategy.

If opponent plays in corner, take opposite corner
if it's available.
[Delivers #62165668] Empty corners strategy.
[Delivers #62166512] Empty side strategy.
Improve tests for empty corners and sides.
Remove initialization for @previous_move.
Better organize strategy tactics.
When recording moves, cast positions to integers.
Rework Block Fork strategy

Extract Board delegation methods into module.
Fix bug in Game#draw?

If last move of game was winning move,
draw would incorrectly report true.
Fix bug in WinOrBlock strategy; seperate into two.

If there were two threats on the board, and a blocking
threat was detected before the winning move, the block
would incorrectly be taken instead of the win.
Change reference from tie to draw
Test computer strategy is unbeatable.
Update readme