Abort releaseing if pandoc is missing. (pandoc was not included in my essential app database, and thus missing on my new machine.)
We are at the point that testing takes waay too long for a release cycle, and fails way too often. Tests through travis are a better indicator than testing just before release.
They are listed in the "supportedsites.html" page.
(YouTube Subtitles are currently flaky in Germany, especially via IPv6)