This keeps things consistent with the general testing guidelines in the Ruby
community. This in turn should hopefully make my life easier as I don't have to
tell people to use this rather odd stlye I was using before.
The AST layer is being removed because it doesn't really serve a useful
purpose. In particular when creating a streaming parser the AST nodes would
only introduce extra overhead.
As a result of this the parser will instead emit a DOM tree directly instead of
first emitting an AST.
Yorick Peterse