Pysolarfocus

Read 'Kessel' input registers and provide them as properties

Fixes 4

v.1.1.1.3
🐞 Bugs
* fix `update()` function, only updating `heating`

What's Changed
* Feature/add holding registers by LavermanJJ in https://github.com/LavermanJJ/pysolarfocus/pull/2


**Full Changelog**: https://github.com/LavermanJJ/pysolarfocus/compare/v1.0.2...v1.1.0

🐞Bugs

* fix wrong heating circuit state mapping