Normalise where headers are installed with the rest of KF
- CamelCase forward includes are installed in both: /include/KF*/Prison/Prison /include/KF*/Prison/prison this way it works even with OS's that are still using case-insesitive filesystems (in 2022...)
- Lowercase headers in /include/KF*/Prison/prison
- _version.h and _export.h in /include/KF*/Prison/
For backward compatibility all headers are still installed in /include/KF*/prison.
Edited by Ahmad Samir