disable Queue.filter for the release

I have doubts about the Queue.filter interface, which is imperative:
  filter : ('a -> bool) -> 'a t -> unit

While that makes sense as a mutable operation on the Queue datatype,
the fact is that all [filter] functions (including for mutable
data-structures such as Dllist and Dynarray) return a filtered copy of
their datatype instead of mutating in place. This convention is used
by the pa_comprehension syntax extension that will happily generate
calls to filter for any data-structure module it is given, expecting
this interface.

Maybe we should consider having
  filter : ('a -> bool) -> 'a t -> 'a t
  filter_in_place : ('a -> bool) -> 'a t -> unit
start versioning batBigarray.ml (no code change in this commit)
batBigarray.ml: make the layout computation 4.02-safe
changelog for 2.3.0
bump version in _oasis
minor: avoid ocamlbuild warnings in <examples/>
minor: fix ocamlfind-related ocamlbuild warning by consistently using -use-ocamlfind
start versioning barArray
Array: make_float: int -> float array
start versionning batList.ml
stdlib 4.02: List.sort_uniq (we had List.sort_unique already)
add a batBytes module simply including ocamlfind's Bytes module
start versionning batBuffer.ml
add 4.02 bytes-related functions to Buffer
start versioning batDigest.ml
minor: Makefile, sort PREPROCESSED_FILES lines for diff readability
add 4.02 bytes-related functions to Digest
start versioning batMarshal.mlv
add 4.02 bytes-related functions to Marshal
make the 4.02 raw backtrace interface available in batPrintexc