clarify StreamLoader requires registered wrapper
clarify StreamLoader requires registered wrapper

liip/LiipImagineBundle,robfrawley/LiipImagineBundle,prolixtechnikos/LiipImagineBundle,prolixtechnikos/LiipImagineBundle,liip/LiipImagineBundle,prolixtechnikos/LiipImagineBundle,robfrawley/LiipImagineBundle