For that, we add parameter safeSearch=none that asks youtube not filter
results before sending them to us.
Note: this parameter could be added to YoutubeSearchIE and YoutubeUserIE
as well, but I don't know what would be the impact in term of unwanted
results. Maybe expose that as a parameter? For a playlist it's different
since the user chose what she put in the playlist.
* print the info_dict in a format suitable to easy adding to tests.json during tests if un-tested fields are detected
* make it possible to put the crc32 in tests.json if the field is too long
* complete the "info_dict" fields in existing tests
* fixed the bugs catched doing this