v1.0.1

The Relatable API key can now be set as a RELATABLE_API_KEY constant in wp-config.php, and the saved key is no longer shown in the settings form. Failed API calls are now logged and shown to logged-in editors in the form response instead of failing silently. Email addresses are URL-encoded in the contact lookup so addresses with a plus sign match correctly, and contact IDs from the API are checked before they are used.