The implementation in D101 has caused problems with being able to run the python example GenFit3pi.py because to be able to use our classes in python they need to have dictionaries generated.
As such, I'm going to revert the changes from landing D101 and make new commits that only apply the following parts of those changes:
- Removal of the deprecated ClassImp macro in all source files
- The improvements to the CMake modules to avoid using old-style CMake stuff like file-level include_directories, etc.