listing more accurate.
Also move the yes_or_no function to it's own module Question to avoid a
module dependency cycle, since Lexer use Parser types and Parser
implementation use Input_handling that defined yes_or_no that use Lexer.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@7767 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02