Map should load on-center

[timothyfcook]

Should load to here, rather than the top of the map:

[chadwhitacre]

The next step for me on this would be to understand SVG coordinate systems:

• http://www.w3.org/TR/SVG/coords.html
• http://sarasoueidan.com/blog/svg-coordinate-systems/

My hunch is that we want to use that for clean zooming and panning ... and centering onload.