1st pass at supporting appending multiple widgets to the container.

Hi Leslie,
You were right, I haven't really been able to work on anything while I've been here.
Today was the 1st time I've really done anything, and I don't anticipate much more until I get home.

This patch changes SVGContainer.append to accept a single widget OR an array of widgets however, I still need to define how widget.setScale(xScale, yScale) works.