Some SVGs missing viewbox attribute

[dougaxe1]

For example: https://github.com/seanherron/Flag-Webicons/blob/master/flags/afghanistan.svg

Embedding these in an <img> tag in Internet Explorer (tested IE11) fails to scale. For instance, the above SVG when rendered in <img width="50"> shows nothing but black (the top left of the SVG). SVGs with viewbox attribute scale appropriately.