Note that shell/server.js is copied into the bundle as shell-server.js,
like before, however now it contains none of the extraneous code that
belongs in shell/client.js.
The original reason server and client code were combined in a single file
was to share helper functions and configuration variables (e.g.
getInfoFile and EXITING_MESSAGE). Now, shell/client.js requires
shell/server.js to access those shared exports.
