Twitch-dl

* Fix compat with older versions of python (71)

* Fix clips download caused by Twitch changes (64, thanks to all participants)

* Add support for new format of clip slug (thanks Loveangel1337)

* Handle videos which don't exist more gracefully

* Added `info` command for displaying video or clip info (51)
* Don't show there are more videos when there aren't (52, thanks scottyallen)
* Fixed Twitch regression for getting the access token (53)

* Fixed clip download issue (45)