Fable 3 related updates

[PierreYvesR]

Removed Babel from webpack
Upgraded Fable to 3.1.1 release

Next would be to fix the Clean target as it doesn't clean the .fs.js files.
I might use the '--outDir' Fable flag and put all the .js files in "tests/build"

[alfonsogarciacaro]

Thanks @PierreYvesR! Although this is just a fork, the original project was created by Maxime Mangel: https://github.com/MangelMaxime/fulma-demo

There's actually a similar PR that we're using as an example of how to upgrade a Webpack application to Fable 3: MangelMaxime#43

[alfonsogarciacaro]

Oh, scratch that! Looking at the files I realize these are changes on top of my PR 😅

I've some doubts about Babel. Fable uses some ES2015 features (like classes, Map, etc) which should be now supported by 95% of the browser market. But still some people may need to support old browsers 🤔

[PierreYvesR]

I'll close it then. Anyway it was a good learning exercise for me ☺️