SpriteInfo: Design + refactor pass
* Updated SVG icons
* Added tab indexes, related #88. Still no tab on radio buttons
* Removed outline on dropdown focus
* Radio icons: fixed redirecting issue, using `div` instead of `a`. Temporary, until radio buttons. Related #156
* All icons: unselectable to prevent highlighting. Radio icons clickable
* SpriteSelector: fixed bottom padding in scroll wrapper
* Standardized use of space units where appropriate
* Reversed box classes for easier readability in Inspector
* Sprite Area: removed unused info button
* SpriteSelectorItems: fixed spacing between rows. Isolated layout + component CSS, now reusable in other context. Items per row is now easily configurable
* MenuBar: refactored structure for clickable items
Using postcss-modules-values with imported values failed on our current basic usage; it is apparently not mature enough to be used yet.
The syntax used by postcss-simple-vars is already familiar to most people familiar with modern CSS build systems.
chrisgarrity