Fix SVG Size Issue for Safari and Mobile Safari

+ Adds method `fixSvgSize` to weather icon component.
+ Calls method in `componentDidUpdate`.
+ Moves svgSupport to separate module that exports bool value.
+ Brings svgSupport into weather icon component as `svg` bool prop.
Support SVG Global and Only Fix SVG Size When Icon Changes

+ Instead of using prop, reference doesSupportSvg as a global variable.
+ Only calls fixSvgSize when icon prop has changed.
Commit Dist
Merge pull request #16 from deseretdigital-ui/fixSvgSize

Fix SVG Size Issue for Safari and Mobile Safari