Node API

[Michael Ball]

Building off #147 Ideas:

We need a function to iterate over all files in a topic file - it should take in a path or a topic file string and execute a callback for each item that would be a page in the lab.

function iterateFiles(topicFile, options?, callback) {}

callback = function (contents, metadata) {}

metadata = {
    type: '',
    url: '',
    sectionTitle: '',
    sectionItems: [],
    topicData: {}, // topic file structure?
} // Maybe this should be an OOP object / have functions for most of these things.