Merge PR #454 - fix activation event

Merge PR #454 - fix activation event

Fix issue where the calculator face's user interface display
was delayed about a quarter second due to the activation event
being a no-op.

Tested-by: David Volovskiy <devolov@gmail.com>
Reported-by: David Volovskiy <devolov@gmail.com>
Fixed-by: David Volovskiy <devolov@gmail.com>
Reviewed-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>
GitHub-Pull-Request: https://github.com/joeycastillo/Sensor-Watch/pull/454