Replace Snabbdom

[davesmith00000]

Snabbdom is the JS Virtual DOM implementation that powers Tyrian's rendering at the moment.

I'd like to investigate replacing it with a pure Scala.js Incremental DOM (or something).

The point of this is to make the SPA and SSR rendering happen via the same process.

Step one is to do the naive thing and just re-render on-change, and replace the innerHtml of the top level element completely. That will work (probably), but will be slow (probably, but is cheap memory-wise), everything after that is an optimisation.

• We'll need a way to run tests in the browser so we can talk to a real DOM - there is a Scala.js selenium thing for that.
• We could also do with figuring out a way to benchmark this compared a) to Snabbdom and b) to other solutions, like Elm and React. Don't need to be the fastest on the market but can't be appallingly slow either.

[davesmith00000]

Will be in the next release when this PR is merged:
#99

[davesmith00000]

Done! Went out with 0.5.0.