Bug#710532: rfc5766-turn-server: broken synopsis

[Oleg Moskalenko]

I accepted all suggested by Justin changes, except that I made the first
line even shorter (I made it just "TURN and STUN server for VoIP"). I
mention the source of the changes in the changelong file.

I put the changes into 1.8.5.3-2 package version and uploaded it:

https://mentors.debian.net/package/rfc5766-turn-server

I also updated the git repository.

I cleaned the upstream page, a little, too.

Thank you, Justin and Daniel, for helping me to clean it.

Oleg