    "Determines if every one of the given boolean values
     (usually a comprehension) is `true`.

         Boolean allPositive = every { for (x in xs) x>0.0 };

     If there are no boolean values, return `true`."
    see (`function any`,
         `function Iterable.every`)
    shared Boolean every({Boolean*} values) {
        for (val in values) {
            if (!val) {
                return false;
            }
        }
        return true;
    }