Foodlist plugin incompatibility

Hi!

1. Here is a part of the WordPress code:

/**
 * Fires after all built-in meta boxes have been added.
 *
 * @since 3.0.0
 *
 * @param string  $post_type Post type.
 * @param WP_Post $post      Post object.
 */
do_action( 'add_meta_boxes', $post_type, $post );

It is clear that the action ‘add_meta_boxes’ has 2 parameters and Polylang expects 2.

2. If you activate the language and translation management for tags, then you will see only tags in the defined language. The problem is that you can’t assign a language for these tags because the language and translations form is not displayed. The reason for this is that the tag add/edit forms are not standard and the authors omitted to provide the actions provided by WP on standard taxonomy add/edit forms.
$tax.'_add_form_fields' and $tax.'_edit_form_fields'