[R] Setting a graph flushed to edges of axes

[Saptarshi Guha]

Hello,
	I need to plot a line graph using lattice so that the endpoints are  
flush with the left and right vertical axes.
	So the scale end points and horizontal axes length should coincide.
	This works
	
	u=newdata[1:100,] #u[,1] is from 1700-1795
	xyplot(u[,2]~u[,1],xlim=range(u[,1]))


	Now u[,3] is a categorical variable and now I want use u[,3] as a  
conditioning variable yet still plot with the above condition
	sc <- list()
	sc$"x"=list(relation="free",tick.number=6)
	p1=u[u[,3]==1,1]
	p2=u[u[,3]==2,1]
	xlim=list(range(p1),range(p2))
	xyplot(u[,2]~u[,1]|u[,3],scales=sc,xlim=xlim,type="l",layout=c(1,2))

	In this case there is some padding between the endpoints and the  
vertical axes.
	How can I remove this padding?

	Many thanks
	Saptarshi