Changing the link for ffmpeg toward a tutorial with an actual mirror of ffmpeg, and with less hassle.
Adding the deendencies to devtoolset-6 and centos-release-scl to provide a C++11 compatible G++
In order to build properly rdf-canonize node nativ module gcc > 5 is needed. Tested on Ubuntu 14.04 with gcc 4.8, it didn't work. I had to install a newer gcc version and it was OK.
* add import-youtube guide inside documentation
* safer to use unlink instead of rm to delete symbolic link, avoid risk of deleting entire directories in case of syntax error
* spelling mistake corrections
* anonymise URLs
* git also needed as dependencies to run yarn install