Studies on the Chinese Crude Drug "Shoma". X. Three New Trinor-9,19-cyclolanostanol Xylosides, Cimicifugosides H-3, H-4 and H-6, from Cimicifuga Rhizome and Transformation of Cimicifugoside H-1 into Cimicifugosides H-2, H-3 and H-4.