Adding character animation

To make sure that the correct animation gets played when the player runs and jumps, we have to extract the run and jump animations from the collada file.

In the Hero class's create function, after updating the anchor point, add the following code to get the run and jump animations:

        // get the animation keys and store it in the anims
        let animKeys = monsterNode.animationKeys.first
        let animPlayer = monsterNode.animationPlayer(forKey: animKeys!)
        let anims = CAAnimation(scnAnimation: (animPlayer?.animation)!)
        // get the run animation from the animations
        let runAnimation = Hero.animation(from: anims, startingAtFrame: 31, endingAtFrame: 50)
        runAnimation.repeatCount = .greatestFiniteMagnitude
        runAnimation.fadeInDuration = 0.3
        runAnimation.fadeOutDuration = 0.3
        
        //set the run animation to the player
        runPlayer = SCNAnimationPlayer(animation: SCNAnimation(caAnimation: runAnimation...