fix sprite side on attack

lib/spellbook.lua

@@ -124,6 +124,10 @@ function attack:cast(caster, target)
     local targetSprite = targetCharacter:has(Tree.behaviors.sprite)
     if not sprite or not targetSprite then return true end
 
+    if sprite.side == targetSprite.side then
+        sprite.side = -sprite.side
+    end
+
     AnimationNode {
         onEnd = function() caster:has(Tree.behaviors.spellcaster):endCast() end,
         children = {