Project-Risk-C : refactor com/risk/controller/CardController.java

• Avoid unused private fields such as 'card'. line 32
• Avoid unused private fields such as 'mapController'.line 33
• Avoid unused private methods such as 'cancelCardView(ActionEvent)'.line 54
• Avoid unused method parameters such as 'event'. line 54
• Avoid unused private methods such as 'checkTrade(ActionEvent)'.line 82
• Avoid unused method parameters such as 'event'.line 82