Update CHANGELOG and Documentation

I've added all changes since 1.15 to the changelog, except all the BLE stuff. I'm not too sure what all the things were that have changed, so @schneider, if you can give me a rough list, I'll integrate them here as well.

Documentation/pycardium/max86150.rst

+``max86150`` - MAX86150
+=======================
+
+.. automodule:: max86150
+   :members: