Fix return of crypto.Signature.sign{Hex,String}.
Fix return of crypto.Signature.sign{Hex,String}.

carldunham/jsrsasign,mattwoolnough/jsrsasign,alex1818/jsrsasign,dongguangming/jsrsasign,cblair/jsrsasign,carldunham/jsrsasign,stephanebachelier/jsrsasign,stephanebachelier/jsrsasign,mdcone/jsrsasign,mdcone/jsrsasign,mattwoolnough/jsrsasign,butlersoftware/jsrsasign,alex1818/jsrsasign,butlersoftware/jsrsasign,austgl/jsrsasign,cblair/jsrsasign,catataw/jsrsasign,catataw/jsrsasign,austgl/jsrsasign,dongguangming/jsrsasign