Extra field for the Presentation category: Subtitles

[beerendlauwers]

Subtitles for presentations would be a welcome sight. For Youtube, there's a Chrome plugin to use subtitles directly in the browser, and you can of course download the video and view it offline with subtitles.

The subtitles themselves should live in a different folder (subfolder of the category?) and be referenced via the YAML metadata.

For subtitle creation, this is pretty interesting: http://www.diycaptions.com/