Display package groupings and relationships in DOT SVG #184

Include package groupings and relationships in DOT SVG using compound=true, but will also need to find (or write) a DOT graph engine that supports this and can also generate a large graph quickly.

https://github.com/knowvah/dot-engine might be an option

Render the graphs in a nested fashion instead of listing the class / package names, but keep the relationships intact.