GnuTLS and Mfx Update

GnuTLS has now been updated to version 3.4.16 while the mfx library has been updated to match Intels 1.19 SDK version. This update to mfx adds support for new functions as well as VP9 and 10b HEVC support on compatible Intel CPUs. As always the latest releases are available on the Projects page while still allowing access to any previously supported releases. The latest FFmpeg build has also been updated to use the latest versions of the new libraries as well.