Fix rendering app authors with homepage or email

When the first author of an app doesn't have homepage/email attributes
set in info.xml then any further author was rendered as `[object
Object]` due to the complex XML node seralized to a JavaScript string.
The logic was fixed so that it converts any of the authors to simple
text.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>