Add timestamp, set to "valid from" which i think could been seen as publish time.
Add thumbnail in more cases, seems to was only done in the embedded data case for some reason.
Switch svtplay test url to an existing video and also one with no expire date.
Also add an additional thumbnail url test regex.
* [infoq] Add audio only format if available
Refactor cookie code into a function.
Renamed formats to http_video, http_audio, rtmp_video
Renamed extract functions to video instead of videos as they return
one or no video.
* [infoq] Rename to _extract_cookies as it more than one
* [infoq] Remove redundant determine_ext
* [infoq] Add comment about hardcoded URL
* [infoq] Use _hidden_inputs instead of messy regex
* [infoq] Probe if audio URL is valid
Make it possible to pass headers to _is_valid_url
* [infoq] Add audio only test
