GitLab

Converted indexing to std::size_t, and fixed the Node templated overloads to properly index any index type (determining what is an index type is a bit of a hack - it should be is_convertible<T, std::size_t> (I think), but I just explicitly wrote down a list)

Added templated Read() function that creates the output variable itself (so you don't need to have a temp variable)

Added emitting for a YAML::Node (instead of the ad-hoc std::ostream overload) so it'll actually emit valid YAML always

Switched from loading test files to testing specific parsing constructs. The tests don't fully cover the span (eventually I'll add more, maybe), but there's a bunch there.
More to the point, the yaml-reader program doesn't do any file IO, so it doesn't require a specific working directory.