Merge pull request #19 from rmsint/phpcr_gaufrette_adapter

Make gaufrette adapter abstract and add a phpcr specific gaufrette adapter
Added XML support
Merge pull request #21 from WouterJ/xml_support

Added XML support
Add route for download action
Refactor DownloadController and add PhpcrDownloadController
Add templating helper + twig extension cmf_download_url