The qTox Project is not associated with the Tox Project in any way, with the
exception of "qTox" using the Tox Projet's "toxcore" collection of libraries.
In particular, the Tox Projet does not own copyright over the qTox Project's
"qTox" collection of software, source code, and assets.
The qTox Project's assets are under the sole copyright of the qTox
contributors, and no partiular rights are granted to the Tox Project.
We can now get the list of video devices with the dshow ffmpeg device
(so, on Windows). Most of this patch is adapted from libavdevice's dshow
private internal interface, which retrieves useful info but is only
designed to log it to stdout. We reimplement that to get an actual list
of devices names/descriptions, that we can then open with ffmpeg the
refular way.