add setInvert() getInvert() (#6)

- add setInvert(bool) and getInvert()
- update GitHub actions
- minor edits

update GitHub actions

update readme.md

add default for functions (#5)

- add default **LSBFIRST** for **setBItOrder()**
- add default **0** for **setDelay()**
- update readme.md
- move code from .h to .cpp
- update example
- update GitHub actions
- update license 2023
- minor edits

add changelog.md (#4)

Develop (#3)

* update build-CI, readme badges, readability, license

initial version (#1)

* initial version