Resources with // get prefixed with base url

[Strubbl]

trafficstars

if the url of an image does not start with http:// or https:// but only with // , then the image gets the base_url prefixed. instead of that it should not get prefixed at all.

dilbert config currently has a workaround, with search/replace in 57aa2446bf442f8f3f633a739b4052dd4f8641aa, which needs to be reverted, when this bug is fixed

[Strubbl]

The bug starts in lines https://github.com/lformella/rss-extender/blob/master/RssExtender.php#L355 ff.