Added Typelevel Scala article.

For review and feedback before publishing ...
One thing to keep in mind is that any non-token changes to the type system are going to not be merge compatible, at least not long-term.  Syntactic changes are probably going to be reasonably doable, though not as straightforward as they would be if Scala had a real parser.

The easiest compiler stuff to do under this regime, I think, will be feature "masking".  Basically, WartRemover on steroids.  Such feature removals should be relatively easy to keep merge-compatible, since they can be handled in a fairly localized fashion.  Some backend changes may also be possible, though the motivation here seems less clear.

Some optimizations might be doable (e.g. based on assumptions derived from feature removal), but it'll be interesting to see how these interact.

Generally speaking, it seems to me that the biggest changes we can effect will be *outside* the compiler, focused on the libraries.