Merge pull request #18 from lemmy/master

Set user-agent to rss-extender in curl call
gulli.com fix
suppress dom warnings
fix some feeds
Support for NZZ (International, Wirtschaft, Finanznachrichten)
Use poor man's inheritance
Merge pull request #19 from ginkel/feature/nzz

Support for NZZ (International, Wirtschaft, Finanznachrichten)
Merge branch 'master' of https://github.com/lformella/rss-extender