Avoid resetting it to zero when the face is activated.
Initialize the variables once when the face is first set up.
This makes it remember the last measurement taken by the user.
It will no longer be overwritten when the watch face activates.
Avoid resetting it to default when the face is activated.
Set the default pulsometer calibration once,
only when the face is first set up.
This makes it remember the calibration set by the user.
It will no longer overwrite it.
Instances of the pulsometer state structure are only passed
to the pulsometer itself and only via the opaque context pointer.
No other code uses it. There is no need to expose it in a header file
so make it an implementation detail of the watch face.
Update the copyrights to include full name attribution to all
who contributed to the pulsometer watch face, including myself.
Also add an SPDX license identifier header comment to the files.
Implements an advanced pulsometer that can be recalibrated by the user.
The main clock face now displays the measured pulses per minute.
The day of month digits now display the pulsometer calibration.
The light button now cycles through integer graduations
which now range from 1 to 39 pulses per minute.
Long presses of the light button cycle by 10 instead of 1.
The watch face's responsiveness to input has been carefully optimized.
The code has been reorganized and generally improved.
