Translated german comments into english.
Further refactoring of the chessboard and game class.
More refactoring on GameStates, Game, Player etc.
Updated to new gamestates in the server class.
Finished refactoring of the basic game and integrated the new
chessfigures.
Fetures:
-undo/redo is now possible
-chessfigure movement
-chessfigure beating
-set another player check
-player change
-timer clocks
-drawing of chessboard, chessfigures and moves
Added the ChessFigure promotion, chessFigure factory plus some minor bug
fixes.
Modified class variables for a consistent code style.
Added the possibility to win and loose a game.
Merge branch 'feature-Chessboard_Game_refactoring' into develop