Babel's own 'browser.min.js' isn't working anymore!

Use instead: https://github.com/babel/babel-standalone

Example:

```
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Greeter</title>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
  </head>
```