Work in Progress

When exporting a single type or function, with no plans to add another to a module, it's great to just do `return TestRunner`. You see this all the time in node, like `module.exports = function…`. It's also better in require statements to be able to say i.e. `local TestRunner = require('./test_runner')` rather than indexing into an object in the require due to the way circular dependencies are resolved.