Generate (possibly exuberant) Ctags style tags for Perl sourcecode.
Recursively follows use and require statements, up to a maximum of max_level.
The implemented tagger, Perl::Tags::Naive is a more-or-less straight ripoff,
slightly updated, of the original pltags code, and is rather naive. It should
be possible to subclass using something like PPI or Text::Balanced, though be
aware that this is alpha software and the internals are subject to change.