Replace deprecated mimetype parameter with content_type
Revert "Drop BeautifulSoup dependency"

This reverts commit 6eca7842358e8c88a774fdc762cba63da1fcf366.
django-compressor requires BeautifulSoup if lxml and python 2 is installed (see https://github.com/jezdez/django_compressor/issues/261)
Extract PlatformPreferences into its own file
Provide available languages using the wirecloud_bootstrap template tag
Retreive workspace resource info (required for public workspaces)
Initial support for public workspaces
Improve error messages raised by the PopupMenuTester.check method
Enable online compression by default