[smarkdown] allow for anim-along shortcut using %along:path:what and %along:-path:what (for reverse=true)
[smarkdown] allow for anim-along shortcut using %along:path:what and %along:-path:what (for reverse=true)

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