Basic boilerplate for prerender project

Features:
- Test harness with [mocha](http://mochajs.org) and [should.js](https://github.com/tj/should.js)
- Basic trivial test
- Basic interface for prerender server

This is currently only a NodeJS module, not yet a standalone application. Whenever there is some actual implementation we can provide a wrapper for a standalone app.

@Magnetme/developers - Ready for review!