Stopping animations prematurely

[MonsterDruide1]

Is your feature request related to a problem? Please describe.
When handling animations on card movements, doing things while an animation is still running is always janky - for example passing on the SwimGame while the FlipAnimation to reveal the cards is still running will leave the card visible in most implementations, even though they should flip back, as the first animation still finishes and sets the card face to "visible"/FRONT.

Describe the solution you'd like
A method like stopAnimation(...) in BoardGameScene should help the situation, and allow the programmer to stop an animation before it is finished if another user action happens that will interfer with the animation.

Describe alternatives you've considered
Another alternative would be to automatically stop the animation on all interactions with that object, but that will probably lead to more confusion. Using Animation.isRunning is currently not possible, as already listed in #318