/**
Returns a new promise that will be resolved when all operations have completed.
Takes both any numer of values as arguments. If an argument is a not a promise,
it will be wrapped in a new promise, same as in `Y.when()`.

@for YUI
@method batch
@param {Any} operation* Any number of Y.Promise objects or regular JS values
@return {Promise} Promise to be fulfilled when all provided promises are
                    resolved
**/
Y.batch = function () {
    return Promise.all(slice.call(arguments));
};