Dynamic wiring example

Example of one way to handle the questions posed in [this gg post](https://groups.google.com/d/topic/cujojs/4sOAK_pR0L4/discussion).  Uses the contextual wire function to show dynamic wiring.  Also shows a few other things: transform pipelines, and destroy examples, plus lots of comments!

Hope this helps.  Let's discuss in the pull request comments as needed!