Saving multiple plots in one file gives incorrect results

[hadley]

devSVG("test.svg")
plot(1, xlab = "", ylab = "", axes = F)
plot(2, xlab = "", ylab = "", axes = F)
dev.off()

gives

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="722.70" height="578.16" viewBox="0,0,722.70,578.16">
<desc>R SVG Plot!</desc>
<rect width="100%" height="100%" style="fill:#FFFFFF"/>
<circle cx="369.68" cy="284.91" r="2.34" style="stroke-width:1;stroke:#000000;fill:#FFFFFF;stroke-opacity:1.000000;fill-opacity:0.000000" />
<circle cx="369.68" cy="284.91" r="2.34" style="stroke-width:1;stroke:#000000;fill:#FFFFFF;stroke-opacity:1.000000;fill-opacity:0.000000" />
</svg>

Given that svg doesn't support multiple files trivially, I'd recommend eliminating the onefile argument and throwing an error if the user attempts to draw more than one