Reset style removes focus styles from focusable elements (a11y)

[missmatsuko]

Applying outline: 0; to all selectors (*) in [reset.scss line 12](https://github.com/imperavi/kube/blob/17f8b65faca5931c421cf38e48b9dabe34dbcb5e/src/_scss/components/_reset.scss#L12] removes the outline from focused focusable elements.

It looks like there's a very subtle focus style added back to form inputs, but links and buttons still don't have any visual indicator when focused.

This makes it very hard to navigate using a keyboard.