when casting a json value to bool, 1 should be true

Created by: firepick1

Benoit, I made the following change in my fork to reduce JSON size. I got the idea from Jansson, which is the other JSON library I use as well.

https://github.com/firepick1/ArduinoJson/commit/f7f2d1dce29fca2886914253c8308cc0221ec580

(ignore the precision change, that's irrelevant)