- allow gallery-dl proxy settings to overwrite environment proxies
- allow specifying different proxies for data extraction and download
- add 'downloader.proxy' option
- '-o extractor.proxy=–PROXY_URL -o downloader.proxy=null'
now has the same effect as youtube-dl's '--geo-verification-proxy'
- adds 'config-file' and 'cmdline-args' options
for both ytdl downloader and extractor
- create 'ytdl' helper module, which combines YoutubeDL creation
and option parsing.
- most likely a buggy mess due to incompatibilities between the
original youtube-dl and yt-dlp.
