Check load_more_widget_html for feed paging
[eighttracks] modernize
[utils] Let request headers override standard headers

What was I thinking when writing this?
[sportdeutschland] add new extractor
[mixcloud] Use a HEAD request when checking if the url is valid
[empflix] Adapt to malformed config XML
[empflix] Extract thumbnail
[ign] Fix extraction of video in articles
[empflix] Revert to XML parser

Don't rely on the XML being broken (if they fix it, our code wouldn't work anymore).
Instead, use the transform function we already have :)

This partially reverts commit c7bee2a7254d31b7c478c0ac33bf23bdeba1c53c.
[sockshare] Fix title extraction (Fixes #3592)
release 2014.08.26
[mfs] Modernize
[muscivault] Add extractor (Fixes #3593)
release 2014.08.27
[generic] Do not download images as videos by accident
[generic] Prevent <video> search from skipping over empty sources (#3546)
[ard] Add suppor for plain ARD downloads (Fixes #3546)
release 2014.08.27.1
[facebook] Match video.php URLs
[vimeo] Move test case to where it belongs