Adding basic Class Diagram docs & some useful files for verification of the tools

I didn't include the jar file of PlantUML, as that has some distribution license issues (i.e. it has a license that Wes might not want, details here: http://plantuml.sourceforge.net/faq.html)
That being said, since the "source" of the image, and image itself are made by us, by their terms of use, we get to determine the licensing of it, so using the input and output for PlantUML is totally alright.