Sets style for all sprites.
@param {String} style CSS Style definition.
function(obj) {
        var i = 0,
            items = this.items,
            len = this.length,
            item, el;
            
        for (; i < len; i++) {
            item = items[i];
            el = item.el;
            if (el) {
                el.setStyle(obj);
            }
        }
    }