Adding HoneypotEvent.
HoneypotListener sends an event and tags the form.

Throwing an exception is now optional.
Adding honeypot tag to composer.json.
Merge branch 'honeypot'
Adding Honeypot::ROW_TAG.

Also moving HoneypotEvent::CAUGHT to Honeypot::CAUGHT.
HoneypotListener adds the name of the honeypot field as a tag.
Adding HoneypotListenerTest.