Add hook_fboauth_properties_alter(), allowing other modules to extend mappable field types

I noticed that you have an empty function named fboauth_field_convert_location() in fboauth.field.inc, so it seems like you thought about importing locations.

For my current project, I'm using the Address Field module to store locations, and the Geocoder module to store latitude and longitude coordinates. I modified fbouath to support importing data into an address field.

I'll just post the relevant snippets for now, given that I've made other changes (to support the name field). If you'd like to roll these changes into dev, just let me know and I'd be happy to submit a patch.

<?php
/**
 * Facebook data conversion function.
 *
 * Converts an incoming Facebook location (which is an object) into an array compatible with the addressfield module.
 */
function fboauth_field_convert_location($facebook_property_name, $fbuser, $field, $instance) {
    $value = NULL;
    if ($field['type'] == 'addressfield' && module_exists('geocoder')) {
      $geodata = geocoder('google', $fbuser->location->name);
      foreach ($geodata->data['geocoder_address_components'] as $key => $components) {
        switch($components->types[0]) {
          // Set city.
          case 'locality':
            $value['locality'] = $components->short_name;
            break;
          // Set state.
          case 'administrative_area_level_1':
            $value['administrative_area'] = $components->short_name;
            break;
           // Set country.
           case 'country':
            $value['country'] = $components->short_name;
            break;
        }
      }
    }
    return $value;
}
?>

Of course, I had to make changes to fboauth_user_properties() and fboauth_field_convert_info() as well, but those were pretty simple:

Modified $properties:

    'location' => array(
      'permission' => 'user_location',
      'label' => t('Location'),
      'field_types' => array('text', 'addressfield'),
    ),

Modified $convert_info, added:

    'addressfield' => array(
      'label' => t('Address Field'),
      'callback' => 'fboauth_field_convert_location',
    ),

This does require geocoder to split the address into component parts. Furthermore, the coordinates are stored in the $geodata object, so you can very easily migrate those into a field with the same method.