Written the add/step feature with the graph. Wrote some helper methods
for that.
Implementation and tests of methods in Board: 2D int array representation, makeMove, rollback, and isValidMove
Merge branch 'master' of https://github.com/rtadinada/cs61b_pj2.git
Implement MachinePlayer with basic minimax
Merge remote-tracking branch 'origin/master'
Update .gitignore