Add C++ API
In order to be able to take advantage of many modern C++ features such as automatic memory managment, it would be useful if Graphviz had a high-level C++ API.
This is spawned from a discussion at the forum. I though it might be better to collect discussion about it in one place.
I realize that this is not a priority for the Graphviz project right now, but since I'm working on creating a new test suite written in C++, I will implement parts of such an API anyway.