Download Creative Commons videos from a YouTube channel

This python script downloads all Creative Commons licensed videos for a given YouTube channel. Downloads are saved to FILEPATH/{video_id}.{ext}, where {video_id} is the YouTube id of the video, and {ext} is the filetype extension. The metadata is also stored in FILEPATH/{video_id}.info.json as a JSON file. An additional utility file at FILEPATH/dl_status keeps track of the download status, and an informational file about the channel is stored at FILEPATH/channel_summary.json.