Adds a simple calculator watch face to the sensor watch capable of addition, subtraction, multiplication, division and exponentiation. Reviewed-by: Joey Castillo <joeycastillo@utexas.edu> Reviewed-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com> Tested-by: Joey Castillo <joeycastillo@utexas.edu> Tested-on-hardware-by: mcguirepr89 <mcguirepr89@gmail.com> GitHub-Pull-Request: https://github.com/joeycastillo/Sensor-Watch/pull/454