Add FIRST_UNIMPLEMENTED_OP instructioon to simplify bootstrapping after adding new bytecode instructions at the end

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14734 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Fix win32unix (introduction of bytes + immutable strings).

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14735 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Add support for floating attributes in class structures and class signatures. (Patch by Leo White.)

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14736 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02