Internal function used by the Tween Builder to return an array of properties
that the Tween will be operating on. It takes a tween configuration object
and then checks that none of the props entries start with an underscore, or that
none of the direct properties are on the Reserved list.
Internal function used by the Tween Builder to return an array of properties that the Tween will be operating on. It takes a tween configuration object and then checks that none of the
propsentries start with an underscore, or that none of the direct properties are on the Reserved list.