Dump PACT plan as json, using the local executor

I needed this feature for generating graphs with graphviz

This python script converts a JSON Graph into a dot file: https://github.com/rmetzger/pact-plan-to-dot

Example: (I can't show it in a higher resolution, due to legal restrictions)
![plan](https://f.cloud.github.com/assets/89049/1458940/8d5352fa-43ae-11e3-8587-6c2b6316474c.png)