New logics and code refinement:
 Card.java:
    removed deckSize parameter

Player.java:
   declaredCard in turn results and parameters is CardValue now
   + dropCard(int card) method to remove a card from the player's deck

GameServer.java:
   declaredCard is CardValue now
   a player drops cards which he decided to put on the board
   + isDraw() method to check for a draw situation