The Spotify provider con handle 'fake responses', so I marked that on the PROVIDERS.md file
- Minor docblock change, lets see if scrutinizer still complains about wrong type checks.
Fixed bug with the Instagram provider and the custom generated html code.
- Since Instagram doesnt provide an html response, the library was generating
  the response. the thing is, that Instagram also support videos. As of now the
  'html' response only supports images.
Added support for vine (http://vine.co)