CppUnit is a C++ unit testing framework.

Starting with version 1.14.0, cppunit may require that your tests be compiled
with a C++11-conforming compiler (e.g. by adding the -std=c++11 flag to g++).
Since this is not yet the default for g++, if you intend on using cppunit with
projects that do not yet mandate C++11, then you may want to stick with an
older version.

graphviz is an optional dependency.  It will be used when creating the
Doxygen documentation if found.
