Update CollectionItem: exception for missing helpers, implement ArrayAccess
Update CollectionItem: exception for missing helpers, implement ArrayAccess

quickliketurtle/jigsaw,tightenco/jigsaw,quickliketurtle/jigsaw,adamwathan/jigsaw,adamwathan/jigsaw,tightenco/jigsaw,quickliketurtle/jigsaw,tightenco/jigsaw