quartz.save "bug"

Hi,

I've just encountered a tiny "bug" in the function quartz.save. It doesn't expand e.g. a leading ~ in the file name.

To fix this one could maybe change the function declaration to:

...
oc$device <- quartz
oc$type <- type
oc$file <- path.expand(file)
oc$dpi <- dpi
...


Cheers,

--Hans