Successful multithreaded PlayerSlots

Test action and Tester class added
Structure implemented:
CSBattleManager -> BattleTeam -> PlayerSlot -> Player

Player slots can now submit Actions to the game manager, which processes
all actions. Player slots have a cooldown delay before passing on the
Action to the BattleTeam, which delays it further, with the purpose of
allowing for future development of combo and group cast skills.