Version 4.0.0 ready

[afpineda]

The firmware has reached version 4.0.0.
See changelog.

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As of version 4.1.0, the code has been updated to work with Arduino core for ESP boards version 3.0.1 (latest at the time of writing).
Please, update your dependencies using the board manager in Arduino IDE.

[afpineda]

As of version 4.1.4, the code has been tested to work with NimBLE-Arduino v1.4.2 (unit test, only).
The firmware still works with v1.4.1. You may update your dependencies using the library manager in Arduino IDE, if you wish.