Reference to Mezzanine media library

Hi Stephen,

To solve [this bug](https://github.com/stephenmcd/mezzanine/issues/610), I wrote a [very simple file library for Mezzanine](https://github.com/thibault/mezzanine-media-library).

It seemed to me it was a recurrent request, but I did'nt find any existing solution. I thought you might be interested to reference this package in the thirt party modules list?

If I'm missing something or if you need any other action from me, please tell me so.

Anyway, I just discovered Mezzanine a few days ago, thank you for your work on this wonderful project.

Cheers.