[playvid] Capture and output error message
[bliptv] Fix resolution of lookup id in some videos

In some videos (for example, http://blip.tv/play/gbk766dkj4Yn) resolving
lookup id would fail, because page at
http://blip.tv/play/gbk766dkj4Yn.x?p=1 would have no "config.id" in
it. Fixed by requesting different URL and inspecting the URL which the
client is redirected to.
[bliptv] Fix \n\n at the end of real_url

See https://github.com/rg3/youtube-dl/issues/3544#issuecomment-53166516
Merge pull request #4333 from ymln/bliptv-fixes

[bliptv] Fix some videos not downloading
[youtube] Don't confirm age when initializing

It seems that all the videos with age restriction use now the age gate method, which doesn't require any confirmation.
[youtube] Use a cookie for seeting the language

This way, we don't have to do an aditional request
[xminus] update tkn extraction regex
Merge pull request #4338 from t0mm0/x-minus-fix

[xminus] update tkn extraction regex
[bbccouk] Fix extraction (#4104, #4214)
[youtube] Add format 313 (fixes #4339)
[youtube] Update test
[test/test_subtitles] Update checksum for vimeo subtitle file
[youtube] Try to extract the video_info from the webpage before requesting the 'get_video_info' pages

The YouTube player doesn't seem to use them except for embedded videos, so we can skip a network request.
But they still provide better error mesagges (for removed videos for example).
[youtube] Simplify code for getting the dash manifest url

video_info contains now the 'ytplayer.config.args' dictionary
[youtube] Add a normal age-gate test video
[myspace] Use player_url for faster download
It keeps reconnecting without it. Download time decreased from 7+ minutes to 25 seconds for me.
[myspace] Add more data to info dict
`uploader` is an artist
`playlist` is an album
[myspace] Handle non-playable songs
I'm adding this because sometimes there is a song page, but you cannot play it.
Example: https://myspace.com/starset2/music/song/let-it-die-maniac-agenda-remix-bonus-track-95799916-106964439
It will be useful for downloading whole album with songs like this.
[myspace] Redirect to other extractors
There are many songs just linked from Vevo/YouTube to MySpace.
Vevo example: https://myspace.com/threedaysgrace/music/song/animal-i-have-become-28400208-28218041
YouTube example: https://myspace.com/starset2/music/song/first-light-95799905-106964426
[myspace] Update tests