There was some concern that we need to indicate which classes we're using in the generated code so that beginners know exactly how to import the bson classes/etc.

We can use the code in https://github.com/mongodb-js/bson-compilers/blob/test-file/make-test-file.js as a starting point.

Open questions: 

• how do we want to display this visually?
• do we only import what we use (therefore do a scan of the exported code) or should we just provide a generic "import" list of things that can be used?
• Is this required for version 1?