public void decreaseValue(final double value) {
        setValue(getValue() - value);
    }
Returns the last value of the Tile. This will be the last value during
an animation.
If you need to get the last value after the animation is finished or if
you don't use animation at all (when using real values) you should use
oldValue instead.

@return the last value of the tile during an animation
src/main/java/eu/hansolo/tilesfx/Tile.java