Support elements with namespaces

Inkscape uses namespaces in it's svg's, like:
```
<sodipodi:namedview
     id="base"
     pagecolor="#ffffff"
     bordercolor="#666666"
     borderopacity="1.0"
     inkscape:pageopacity="0.0"
     inkscape:pageshadow="2"
     inkscape:zoom="1.1607422"
     inkscape:cx="202.69645"
     inkscape:cy="657.84284"
     inkscape:document-units="px"
     inkscape:current-layer="layer1"
     showgrid="false"
     inkscape:window-width="960"
     inkscape:window-height="1152"
     inkscape:window-x="0"
     inkscape:window-y="0"
     inkscape:window-maximized="0" />
```
This wasn't supported by the properly close svg tags regular expression.