[BioC] plot axis in pROC

[David martin]

library(pROC)
data(aSAH)
plot.roc(aSAH$outcome, aSAH$s100b)

The x and Y axis do not start nearby, there is an inner margin in the x 
axis in you maximize the image .

I have tried usng the options xaxs = "i", yaxs = "i" but still an inner 
margin.
How can i fix this??

thanks,

david