merge master into webdav-injection

apps/files/ajax/upload.php

apps/files/js/file-upload.js

apps/files/js/filelist.js

apps/files/js/files.js

apps/files/l10n/ast.php

apps/files/l10n/el.php

apps/files/l10n/tr.php

apps/files/lib/helper.php

apps/files/templates/index.php

apps/files_external/l10n/ca.php

apps/files_external/l10n/cs_CZ.php

apps/files_external/l10n/sl.php

apps/files_sharing/css/public.css

apps/files_sharing/js/public.js

apps/files_trashbin/js/trash.js

apps/files_trashbin/l10n/ar.php

apps/files_trashbin/l10n/ast.php

apps/files_trashbin/l10n/bg_BG.php

apps/files_trashbin/l10n/ca.php

apps/files_trashbin/l10n/cs_CZ.php