Add support for AI for path-searchable games

[andrewjmeier]

• Subclass Player to create a Computer Player class
• In the State Machine, check to see if a player is a computer, if it is, go figure out the move to be made
• Implement AB pruning search algorithm to find the best move for the computer
• Add two methods to the game class (getPossibleMoves, evaluateState) that must be overridden in the subclass
• Update start game view to provide an interface to make a player a computer player
• Add documentation explaining which types of games can have this computer player and the necessary methods to override

@konnorbeard @kevinkim91

[andrewjmeier]

@kevinkim91 @konnorbeard it's not letting me assign this to multiple people...