Automatic Documentation Generation (dgeni)

This is a draft effort at generating docs from the src.  To try it out do:

```bash
npm install
gulp dgeni

npm install -g http-server
http-server docs
```

The browser to http://localhost:8080/

The documentation is generated by dgeni using the traceur compiler to parse the source code into an AST for each module.
This is then manipulated to extract each module's exports and then rendered to HTML files in the `build/docs` folder.

Any JSDOC style comments in the code will be extracted and attached to the relevant bit of the AST and so used in the generated docs.

All the configuration, processors and templates for this are stored in the `docs` folder.
The templates right now are very simple (`docs/templates`). We can have template inheritance and includes to provide more sophisticated layouts and content.

More processing needs to be done in dgeni to extract the navigation and also to do a better job of extracting useful information from the source code.
How do we run those tests? I didn't see changes to the karma config. We should run them on Travis to prevent regressions. Also we should run the docs generation on Travis (not required to address this in the current PR).