Jibri Install FFMPEG

[nightstryke]

In the Ffmpeg with X11 capture support section there's only install/build instructions for Ubuntu 14.04 where as it's stated that Jibri Install instructions are for Ubuntu 16.04.

While you can install Ubuntu 16.04 version of FFMPEG and I am sure it will run just fine, if you have build instructions of FFMPEG then it would be better to tell Ubuntu 16.04 users to use this repository. I only say this so as not to confuse users and cause unnecessary problems.

If building Jibri for Ubuntu 16.04 (xenial xerus), the mc3man repo provides packages. They can be used by the following in Ubuntu 16.04:

sudo add-apt-repository ppa:mc3man/xerus-media
sudo apt-get update
sudo apt-get install ffmpeg