Action: Use [Set.of_list].

plus a comment on compatibility with ocamlyacc
when there are end-of-stream conflicts.

Conflicts:
	TODO

There remains to document this feature and to produce better names.

May wish to move to ocamlbuild in the future.

No observable impact.

Not useful in practice; preparation for further changes.

Documentation update.

README update.

  (Even though at least cutdown would deserve investigation.)

Modify [Engine] to give access to the positions of the lookahead token.
  Use a tainted dummy position to help debug.