[generic] Set default-search to error

This prevents users from submitting bug reports where they mistyped a URL, and prevents me from getting a weird video when holding shift and thus searching for :Tds
[YoutubeDL] Show download URL when -v is set

This will allow us to debug issues like #3204
[newstube] Capture error message
[newstube] Replace test
Merge branch 'master' of github.com:rg3/youtube-dl
[arte] Manually set the rtmp play_path (fix #3198)

rtmpdump doesn't parse it right
[ninegag] Fix extraction
Merge remote-tracking branch 'upstream/master'