[oe] [meta-multimedia] Add a working Tvheadend recipe

[Peter Bašista]

Hi,

a few months ago, I have created a PR on GitHub about adding a working
Tvheadend recipe:

https://github.com/openembedded/meta-openembedded/pull/91

I would like to have it merged, because I believe that Tvheadend can be
very helpful with setting up a TV streaming server on linux-based DVB
receivers.

But it seems like no one has looked into it yet. Therefore, I would like to
ask here how the process works.

Thank you.

Regards
Peter Bašista