wrong axis scale when plotting on a filled.contour plot (PR#3596)

Full_Name: Marco Gruteser
Version: 1.7.1
OS: Win XP
Submission from: (NULL) (129.34.20.16)


Let's generate a dummy filled.contour plot

x <- 1:10
y <- 1:10
z <- array(rep(0, times=100),dim=c(10,10))
filled.contour(x,y,z)

And try to add some points to it, e.g.

points(8,2)
points(6,2)

The points show up misaligned with the axis 
somewhere at 9.9,2 and 7.5,2

It appears that the "z value legend" on the right
may have distorted the axis.