Resolve "Reorder new button :active and :focus states, and add :active:focus combo"

This change reorders the button pseudo classes so that the :focus state does not override :active. In addition, it ensures that :active and .selected buttons still have a focus states, just one that doesn’t override their properties, but simply adds the focus ring.

Before	After
Screen_Recording_2020-02-18_at_4.19.48_PM	Screen_Recording_2020-02-19_at_1.35.25_PM

Closes #628 (closed)