after a lot of deliberation I think I'm starting to prefer GPLv3 over
GPLv2 for copyleft, and this is a case where my rationale benefits from
the additions of the Affero clause
this is server side, and a more standard format, and thus I like it more
than mermaid, which I've been using at work. but, I really wanted a
server-side option (see my manifesto) for drawing relationship graphs,
for D&D stuff of all things.
this adds an optional 'graphviz' feature to package installation which
consequently depends on pydot