1.6.0

Adds an IIFE version (in lib/browser.js) that can be used in headless tests, for example:

const puppeteer = require("puppeteer");
const script = require.resolve("@wildpeaks/snapshot-dom/lib/browser.js");

const browser = await puppeteer.launch();
try {
  const page = await browser.newPage();
  await page.goto("http://localhost:8000/", {waitUntil: "load"});
  await page.addScriptTag({path: script});
  const snapshot = await page.evaluate(() => window.snapshotToJson(document.body));
  console.log(snapshot);
} finally {
  await browser.close();
}