More tweaks to D3 demo

* Start in Columbus View mode
* Increase minimum size of SVG on large monitors
* Adjust text size/placement of SVG year label.
Merge pull request #7 from emackey/tweak-d3cs

More tweaks to D3 demo:
Start in Columbus View mode
Increase minimum size of SVG on large monitors
Adjust text size/placement of SVG year label.