Steps to cropduster v5

[fdintino]

• Make “original” image path the actual original image path, not upload/path/basename/original.ext
• Optional distributed/async thumbnail generation with celery
• Abstract thumbnail generation “engines” (e.g.: pillow, gifsicle, ffmpeg)
• Multi-format feature: A single “image” able to be stored in multiple formats for optimal file size (e.g. using jpeg2k or webp with jpeg falback)
• Cinemagraph support (looping mp4/ogv/webm video files using ffmpeg with gif fallback; requires multi-format feature and thumbnail engine feature)
• Allow filters to be passed as options to Size (e.g. grayscale)