[fix] google-videos: parse values for 'length' & 'author'

The 'video.html' template from the 'oscar' design supports replacement
for *author* and *length*.  Google-videos does not have an author, alternatively
the publisher info from is used for the *author*.

Hint: these replacements are not supported by the 'simple' design.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>