Fix streaming admin server to work on Ubuntu 16.04 and add startup script for /etc/init.d

[gkenaley]

By submitting a request, you represent that you have the right to license
your contribution to the community, and agree that your contributions are
licensed under the Apple Public Source License Version 2.0.

For existing files modified by your request, you represent that you have
retained any existing copyright notices and licensing terms. For each new
file in your request, you represent that you have added to the file a
copyright notice (including the year and the copyright owner's name) and the
Darwin Streaming Server's licensing terms.

[gkenaley]

The streamingadminserver.pl incompletely renders web pages and is non-functional when hosted on Ubuntu 16.04 (and probably on many other recent Linux distros). After considerable searching I found a fix at https://vk.com/wingcatlab?w=wall-99790498_55 and translated it from Russian. The fix required a companion change to parse_xml.cgi. The other thing I found was missing was a startup script "darwin-streaming-server" for /etc/init.d - it can be installed with "sudo update-rc.d darwin-streaming-server defaults 95".