implementation module UtilMapState

UtilMapState :: (.a .state -> (.b, .state)) [.a] .state -> ([.b], .state)
UtilMapState _ [] state
	=	([], state)
UtilMapState f [h : t] state
	#	(h`, state)
			=	f h state
	#	(t`, state)
			=	UtilMapState f t state
	=	([h` : t`], state)
