Skeletal animation scrubbing

[ghost]

Four new methods were implemented:

• void SkeletonAnimation::FastForward(Number)
  • Jumps forward in the animation by a specified amount of time.
• void SkeletonAnimation::Rewind(Number)
  • Jumps backwards in the animation by a specific amount of time.
• void SkeletonAnimation::setPlayhead(Number)
  • Sets the 'playhead' of the animation to a specific point.
• Number SkeletonAnimation::getPlayhead()
  • Gets the playhead's position in the current animation.