make SubFS use keyword arguments in calls to listdir(), to allow new keywords to be added in FS subclasses
make SubFS use keyword arguments in calls to listdir(), to allow new keywords to be added in FS subclasses

PyFilesystem/pyfilesystem,pombreda/pyfilesystem,pmitros/pyfs,Konubinix/pyfilesystem,piranna/pyfilesystem,flying-circus/pyfilesystem,zopyx/pyfilesystem,rivenz/pyfilesystem,pmitros/pyfs