Fix for /e modifier deprecation.

This should resolve issue [#30](https://github.com/bastianallgeier/kirby/issues/30). Also, issue [#85](https://github.com/bastianallgeier/kirbycms/issues/85) in the KirbyCMS repo.

Also: http://getkirby.com/blog/how-to-add-a-rss-feed#comment-1180089170