Making Bangle.js more responsive - please test!

At the moment Bangle.js responds to button presses when you release the button, rather than when you initially press it. It's because initially some users wanted the ability to detect a long press of the button (which you can't know when the button is first pressed), but the time taken to press the button and release it is quite noticeable, and does really make the Bangle seem less responsive than it could be.

Despite detecting long presses seeming like a good idea, very few apps actually do it, so thyttan has been working on seeing what happens if we respond when the button is pressed rather than released: https://github.com/espruino/BangleApps/issues/3435 (apps could still use button release if they need to detect long presses)

You can now test this out by installing the https://banglejs.com/apps/?id=setuichange app - and I'd really like to her your thoughts after trying it...

Does this break anything?

• run/runplus currently start/stop recording when the button is pressed (but you hold the button to exit) - so those need tweaking
  
• One or two apps (like spotrem) directly access the button event and then won't see an improvement here
  
  

But personally, I feel like the difference in perceived speed when moving from clock->launcher and back (which is what happens 80% of the time) makes this more than worth any small inconveniences