* Backport from ESP32
* Use new library layout (.../src)
* Cleanup test case.
* C++ style cast required.
* Whitespace
* Inlining via header has better baseline ROM footprint.
* Reordered functions for better code-compare to master
* Reduces ROM footprint some more.
* Avoid unnecessary parameter passing - refactoring, same generated footprint.
* Reformat example sources