Merges plugins default values.
string $type: The name of the plugin type option.
protected function mergePlugin($type) {
if (($options = $this
->getOption($type)) && isset($options['options'])) {
$plugin = $this
->getPlugin($type);
$options['options'] = $options['options'] + $plugin->options;
$this
->setOption($type, $options);
}
}