- added custom item_actions to listings
- added special function in order to register pages that aren't present in the menu
- removed useless test.hbs
- added wp_nonce_field & params functions to Twig
- created a separate "newsletter/form.html" (copy of editor.html) but properly formatted
- fixed issue on bulk action being run even without any items selected
- added WP like feature regarding item selection, if all items are checked, it also checks the header/footer checkboxes
- fixed issue where the selection state was not properly reset
- added List column to subscribers
- added json_encode/json_decode to Twig
