Always blur focus from the event trap before updating content editable

Toggling the content editable flag while the element is in focus will
sometimes stop the browser from allowing the IME to be activated.
Blurring the focus and then restoring ensures the browser re-evaluates
the IME state after the content editable flag has been updated.
Correct subscription to the blur event

The blur event should always be on the event trap, as the event should
indicate when the local input is no longer active.
Merge pull request #347 from peitschie/ime-activation-fix

Always blur focus from the event trap before updating content editable