We used to store a full vector of "views" of the registered test infos, so that it can be retrieved externally. However, the only user of that interface left was `Session`, specifically `Session::applyFilenameAsTags`. By moving the adding of the filename tags into the `ITestCaseRegistry` interface, we avoid storing the vector and make the initial test registration faster. The new code is ugly and shows a design/layering issue, but no worse than the previous approach did.
The old internals reached into the global hub to stash the allocation(s) for enum value -> string value there, then kept around a potentially invalid (in case the hub was cleaned up) reference into it, going through whole bunch of virtual dispatch in the process. The new internals just store the data in a static variable inside the `StringMaker` specialization. This avoids potential lifetime issues, avoids all virtual dispatch and (almost) reduces the include bloat in the main header path. The reason for (almost) there is that for full include correctness, `EnumInfo` needs `<utility>` include for `std::pair`. However, this brings in things like `std::relops`, because the std headers in C++ are dumb. As this was not included before, and instead we relied on `std::pair` existing in an internal stdlib header that we transitively included, the full include size ends up bigger than before.
To keep the compilation firewall effect, the implementations are hidden behind a PIMPL. In this case it is probably not worth it, but we can inline it later if needed.
The license file was renamed with 6a502cc2f5fedd59b3495b58708f0d6d987ed9e1
This also required splitting out Listener factory from the reporter factory hierarchy. In return, the listener factories only need to take in `IConfig const*`, which opens up further refactorings down the road in the colour selection and implementation.
This should also be done for test files, but that has lower priority.
This commit also strips the old copyright comment header in touched files, as those will also be replaced with a more standardized and machine-friendly version.