Fix logo rendering problem in Chrome

The logo SVG wasn't rendering properly. Now it's loaded in the HTML file as an
object rather than an img and the size is adjusted with the div. Loading as an
object makes it render more crisply.

Also, the SVG itself was changed so that it doesn't have a predefined size.
Instead, it's got a predefined viewport. For some reason, Chrome likes that
more than a predefined size and thus it renders the SVGs properly.

For more info, see:
http://henkelmann.eu/2010/12/16/display_svg_image_same_size_in_decent_browsers
Merge branch 'logo_rendering'