fixes for #3

[caseyfaber]

fixes singletons not exporting or importing
fixes collection links not restoring
#3

[pauloamgomes]

Believe that is not exactly what we need, as we should iterate over a collection link field (the collection field can be multiple) and not the full entry fields.
Think below should be more appropriate and fixes the issue:

        // Handle collection link fields by updating the referencing ids.
        foreach ($collection['fields'] as $field) {
          switch ($field['type']) {
            case 'multiplecollectionlink':
            case 'collectionlink':
              foreach ($entries as $entry) {
                if (!isset($entry[$field['name']]) || !is_array($entry[$field['name']])) {
                  continue;
                }
                foreach ($entry[$field['name']] as $idx => $value) {
                  if (isset($value['_id']) && isset($idsMapping[$value['_id']])) {
                    $entry[$field['name']][$idx]['_id'] = $idsMapping[$value['_id']];
                  }
                }
              }
              break;
          }
        }
        $this->module('collections')->save($collection['name'], [$entry]);

Note that also moved the save out of the loop (that was a bad mistake I did before)

[ericsolberg]

Any chance this fix is going to get merged?

[pauloamgomes]

Thanks @ericsolberg , yes, as I found some free time to do what requested.. the PR needs an update.