Refactored to follow the tic tac toe

1. Game state is represented as a two dimensional array and deltas of
the last move.
2. The game works so far, and all tests pass.
3. Next I will review the comments and documents….
Updates comments and variable names

1. Change all coordinate to delta for consistency.
2. Update the comments,
Merge pull request #3 from chongzizil/Refactor

Refactored.