Navigating the tachyons docs

[iteles]

The tachyons docs are really great so there is no need to rehash the documentation within this learn repo. However, there's a lot up there and for beginners, it might be useful to have a little 'getting started with the docs' if you're learning tachyons as opposed to using the docs for reference.

What are people's thoughts on this? Will it just make the learn-tachyons repo stale quicker as the docs change?

[nelsonic]

@iteles I was thinking the same thing; the docs are great but it would be good to condense them into a "Learn this first" list.

[iteles]

Closed with the above commits for now, can be reopened when required 👍