Write stress tests

[200sc]

Write a test harness which will repeatedly:

1. Generate a random, arbitrarily large bebop.File structure
2. Write this structure out to a bop file (with formatting tooling)
   2a. Randomly adjust this file in ways that maintain it as a valid bebop file (newlines and other whitespace, comments, etc)
3. Read this structure back in
4. Confirm that read structure matches the original structure
5. Generate a go file from this new structure
6. Confirm this go file compiles
7. Confirm this go file contains a type definition for every type in the bebop definition

A harness like this would have detected #18 sooner.