[TRACKER] v0.2.13

[KaruroChori]

Original tasks for v0.2.13 have been postponed. Todo list for my own reference:

• Fix the linking issue of fmt.
• Move the current visitor patters into a proper file and expose template variants.
• Remove legacy print and place print2 as replacement.
• Finally replace serialization functions used in the new print.
• Make sure the full serialization process is going to be without memory allocations and exceptions.

#28 is the PR to finish this milestone.

[KaruroChori]

Final tasks delayed to a different release as a lot more has been done to improve the layout of the project and it is enough for a new release. Just some tests left prior to that.

[KaruroChori]

The new print is twice as slow as the original one. This is because a trivial recursive function is much more optimized compared to the extra logic needed to handle a depth-first iterator.
Considering the new implementation can work on XML documents of arbitrary size and depth, it has a clear advantage. The stack-based implementation is limited to the size of the allocated stack (and what remains of that).
However, it is not absurd to think someone might want to take faster version as their stack size if totally fine for the type of documents being serialized. I might want to restore support for the older implementation just because of that.