Added a class User which inherits from player. This makes it possible for two users to play against each other. Now two users play against each other by default.
Merge branch 'master' of github.com:marsj725/TDDD49 into twoPlayers

Conflicts:
	GUI/BoardGUI.cs
	GUI/MainWindow.cs
	Mediator.cs
Added so that the log says who's turn it is if the user tries to click on something else than its own pieces.
Merge pull request #20 from samni698/twoPlayers

Added a class User which inherits from player.