Psuedo code:
// Setup:
sprite = new SkeletonAnimationSprite(skeletonData)
sprite.addAnimationState() // makes a second animation state available
// Any time later:
sprite.setAnimation("walking", true, 0) // animation state zero
sprite.setAnimation("attacking", true, 1) // animation state one
// Set slot image:
sprite.skeleton.setAttachment("slotname", "attachmentname")
