Clean up output.js file

[macparadeis]

The output.js file needs to be refactored to match code style guidelines. Primary issues relate to redundant comments and missing or inconsistent function definitions. This is a subset of issue #89.

[math-witch]

The function getExportMetadata has a return statement with multiple expressions that are longer than 80 characters. At best, adhering this part of the file to the style guide would involve making each expression more difficult to read. How should we proceed with reformatting this portion of the code/should this code chunk still be reformatted?