[Planning] Drop useless notice.
[Detail] Use the composition, Luke.
[Code Clean] Tiny code replacing.
[Code Clean] Tiny cleanup.
[Detail] Encapsulation.
[Detail] Another renaming.
[Code Clean] Class decomposition.

Scoped feature and scope attributes concept have been moved into their own file.
[Code Style] Part of documentation is more doxy now.
[Code Style] Naming.
[Code Clean] Removed unnecessary include.
[Code Style] Styling and including.
[Documentation] Handy note about scoped feature.
[Deprecation] Remove deprecated file just as planned.
[Detail] Revert hpp/ipp decomposition.
[Planning] Slightly changed my mind.