Updated animation code to look smoother.

The example sprite is based off an old Photon Storm tutorial (available here: http://www.photonstorm.com/flash-game-dev-tips/flash-game-dev-tip-12-building-a-retro-platform-game-in-flixel-part-1). I updated loadGraphic to accurately reflect the rectangular dimensions of the sprite and also changed the walk animation to reflect the intended motion from the original tutorial ([0,1,0,2]).