YouTubeKit v0.0.3

New features:

• Added support for video download chunking
• Added a new extractor for faster download speeds
• Added implementation for YTDownloader.bestFormat(for:quality:fileFormat:)
• Added cancel support for downloads with new protocol (Cancellable)
• Fixed random order for YTVideo.availableQualities and added YTVideo.availableFormats
• Added support for YouTube video thumbnails