CardManager
 - Add function to allow cards to be draggable.
GameManager
 - Connect signals from Scene and CardManager
 - Implement functions to skip declarations.
StateManager
 - Connect signals from the declaration phase.
Scene
 - Add cardsMoveable boolean member.
 - Alter mouse press event to allow cards to be dragged.
DeclarationPhase
 - Add signals to be emitted on the initial trick.