Run samples via Polytrix

I've been working on a gem called [Polytrix](https://github.com/rackerlabs/polytrix), which started out as a gem for doing polyglot compliance testing (checking code samples in multiple languages had the same behavior), but has some useful testing and documentation features even for pure ruby projects.

It will run all the samples/*.rb and samples/*.sh files and then convert them to markdown in docs. That can than be served via viewdocs.io, middleman, or whatever. So this can take the place of Aruba/Relish, and also avoid the need for something like Docco.