Modified config to pass auth info through env vars

- added source command to npm start in packag.json
- renamed config.json to config.js so that variables can be used
Renamed book.js to document.js
Added deployment instructions
Added processHTML.js script

- When executed on an HTML file, it appends the necessary IDs and
elements for Fixit to recognize it.
- config.js now includes a list of commentable units of text.
- Added a jsdom dependency to package.json.
- Removed stale commented-out code from fixit.js.