Opening a H.264 stream from a URL

[basvandijk]

At work I'm planning to decode H.264 streams from camera's and I hope I can use your library for that.

The first goal is to open a URL of the H.264 stream. I noticed that the InputSource type only has a File and Camera constructor:

  data InputSource = File FilePath | Camera String CameraConfig

We probably need a separate URL InputSource.

@TomMD, it was mentioned by @acowley to add you to this issue because you recently added the InputSource support. He also mentioned this link to an example of opening a video stream from a URL:

http://stackoverflow.com/questions/23020294/c-ffmpeg-api-get-video-stream-from-https-link

[proger]

I just put the URL into pretending it's a File in #35 — AFAIK ffmpeg doesn't really tell them apart from the surface.