moved sort_by_attr to FileListing, #167
removed url_join, #167
removed url_strip, #167
removed get_version_filename, #167
moved get_file_type to FileObject, #167
moved get_breadcrumbs, get_filterdate and get_settings_var to sites, #167
removed is_selectable, #167
moved convert_filename to forms, #167
forms cleanup, #167