[anim] rewritten viewBoxAs with the same improvements as with attribute animation
[anim] rewritten viewBoxAs with the same improvements as with attribute animation

twitwi/deck.js,ProgRT/deck.js,ProgRT/deck.js,alexjobs/deck.js-1,ProgRT/deck.js,twitwi/deck.js,twitwi/deck.js,alexjobs/deck.js-1,alexjobs/deck.js-1