Fix fixSvgSize

+ Sets height to current height instead of mucking with display. I
was seeing some jerky issues in other browsers.
+ Removes unused supportsSvg component method.
Adding a key prop seems to fix svg size

Adds key prop to icon <img /> tag and removes unused code.
Merge pull request #17 from deseretdigital-ui/fixFixSvgSize

Fix fixSvgSize