Changes to show finishing animations with an explosive effect. (e.g. shown when turtles get shot in Diamondus)

eventframe.cpp
*) The drawing routine no longer ignores negative finish animation values. Instead 128 is added.
*) If 128 is added that means an explosive effect should be used. A boolean is set for this.
*) If the boolean is set the finishing animation will be drawn six times. The animation will be moving in a half circle trajectory.