Help for writing an app (running zones using Karvonnen method)

I like Halemmerich's suggestions, especially the vibration on changing zones.

1. If there's a vibration on zone change, maybe it should be handled in settings (like buzz on distance, on time, etc...)
   
2. About the bpm for the alert that's a good idea, so that people can adjust their max heart rate. About this topic, most physicians consider going 100% or close of your heart rate's max to be a threat for one's life. It's the kind of effort that can be sustained only for a few seconds and that is extremely demanding. Finding your max heart rate this way is not encouraged (yes I did anyway). We don't want to encourage people to trigger the alarm zone...
   
3. In the app download sections, in the readme sections, there should be a word about how to get minimum heart rate. It should be when you wake up before you made any move. That's where the heart rate is at its lowest. My min bpm is at 58 during the day, but drops down to 48 when I wake up, that makes a noticeable difference for the calculation of the Karvonnen zones.
   
4. I'm excited about trying this out :)) !!
   
5. I tried it. Looks nice ! But...
   
6. All the settings are ignored. Min and max hr are ignored, the number of boxes, and so on.
   
7. Because it's unconvenient to remember if we have to swipe right or left to get to the other screen, I think that any wipe action should bring the other part of the app.
   

3 digit pulse overdraws on the ring on the right side, so the ring probably needs to be drawn again after the pulse has been updated

Fix in this PR

EDIT:

All the settings are ignored. Min and max hr are ignored, the number of boxes, and so on.

Fix for settings added to the PR.