Dry run for downloads

[Owez]

If there's a massive channel and you just want to download the videos after stopping the big download session, you probably don't want to refresh your massive metadata. To fix this, having some --dry argument in the refresh config would be good. Need to differentiate:

• Not pulling new metadata (this issue)
• Not downloading videos (future issue)

So that these two options wont collide with naming. I don't want --no-.. because that's a bit ugly.

[Owez]

This will be part of the 1.1.1 release, I've thought about it a bit and --no.. is the best of the bad options. The problem is the future issue with "dont download videos" could be done right now with just:

yark refresh x --videos=0

[Owez]

You can now use --skip-metadata and --skip-download to do either option, I implemented the future issue in here