Add flipping to player's sprite

[DinPX]

The sprite is static and so doesn't convey the movement direction to the players, it would be nice to add flipping to the sprite

Robi's (Sprite) flip_h will toggle depending on the move direction (possibly also based from where they're aiming at)

It's values aren't on the AnimationPlayer of its parent Skin so it can be adjusted freely

Also it works when the Sprite would be converted into AnimatedSprite