es5 inheritance

Spawner.js

exports.spawn = function(parent, props) {
    var key,
        defs = {
            _parent: { value: parent, enumerable: true }
        };

    for (key in props) {
        if (props.hasOwnProperty(key)) {
            defs[key] = {
                value      : props[key],
                enumerable : true
            };
        }
    }

    return Object.create(parent, defs);
};