Improved BehaviorModel public interface:
* removed generic type;
* Behavior type again specified through BehaviorModelAttribute;
* SupplementBehaviorType can be override if BehaviorModelAttribute can't be provided, e.g. SimpleBehavior<T>.
Added IStatusEffect behavior specifying an icon on the card with descriptive text;
Implemented displaying IStatusEffect icons on card;
Spell_Freeze now use IStatusEffect to place a "frozen" icon on the affected card.