lib/lmd_common.js
function (config, configDir) {
    config = config || {};
    if (typeof config.extends !== "string") {
        return config;
    }

    var parentConfig = tryExtend(readConfig(configDir, config.extends), configDir);

    return deepDestructableMerge(parentConfig, config);
}
function (config, configDir) {
    config = config || {};
    if (typeof config.extends !== "string") {
        return config;
    }

    var parentConfig = tryExtend(readConfig(configDir, config.extends), configDir);

    return deepDestructableMerge(parentConfig, config);
}
Merges all config files in module's lineage

@param {Object} config
@param {String} configDir