Update Miradasalsur.

Fixes #1193922 [Updated recipe for Miradas al Sur](https://bugs.launchpad.net/calibre/+bug/1193922)
News download: Respect more default conversion settings

News download: Apply the default page margin conversion settings. Also,
when converting to PDF, apply the pdf conversion defaults. Fixes #1193763 [Private bug](https://bugs.launchpad.net/calibre/+bug/1193763)
Update taz.de (RSS)

Fixes #18 (RSS Recipe broken: Taz RSS)