I agree. Let's not wrap this entire block into an onload script.

A better way to do this would be like our GoogleMaps plugin.

It first has checks to see if the script is loaded, like so https://github.com/mozilla/popcorn.webmaker.org/blob/master/public/templates/assets/plugins/googlemap/popcorn.googlemap.js?source=c#L207-L209. It waits for the document to have a `<body>` and then adds the maps api script.

Afterwards it uses a polling modules type system seen https://github.com/mozilla/popcorn.webmaker.org/blob/master/public/templates/assets/plugins/googlemap/popcorn.googlemap.js?source=c#L166-L191 to finish the setup once it knows the maps script is present.