Allow downloading of the app

[JoelCreatesGames]

probably will need a manifest, and to stop fingerprinting (requires .json file which can't be loaded from CORS)

[JoelCreatesGames]

this turned out to be a bit more complicated than thought

1. If you download from your browser's "save page as" it will save the app as it currently is, which means you will see the app "twice" when loading locally. This is because its saving the DOM as it was when the user viewed it, and then the javascript will generate the app again

2. If you try to download the zipball from http://github.com/BestieJoel/minecraft-build-reference/zipball/master then all the links are expecting it to be served from /minecraft-build-reference/ meaning the links would have to be updated or the user would have to know to update their files/links

3. I've done PWA's in the past, and have always had issues around updating them and the client having an older cached version

I think for the time being this will be put on hold