not updated:
- stdlib/array - the proof is broken
- ring_decision/ - not replayed, proof broken
- in_progress/, util/, prover/bench/ - not replayed

updated the DTD accordingly, and all session files

fix obsolete sessions

* declare range types and float types,
* use integer (resp. real) literals for those types through casting,
* specify how to print them in drivers.

Change in syntax
* use

  type t = < range 1 2 >   (* integers from 1 to 2 *)
  type t' = < float 4 12 > (* float with 4 bits in exponent and 12 in mantissa *)

  the two projections :
  t'int
  t''real

  and the predicate :
  t''isFinite

* Restrict the use of "'" in whyml:
  Users are not allowed to introduce names where a quote symbol
  is followed by a letter. Thus, the following identifiers are
  valid:

  t'
  toto'0''
  toto'_phi

  whereas toto'phi is not.

Note: we do not yet support negative numbers in range declaration
and casting of a literal.

still problematic:

  tests-provers/div
  tests-provers/div_real
  check-builtin/int
  bts/fsetint
  logic/bitvectors
  logic/einstein
  logic/genealogy
  bitvectors/power2
  bellman_ford
  knuth_prime_numbers
  vstte12_combinators
  hoare_logic/blocking_semantics5

known issues:
- Timeout is not always recognized
- why3 tactic does not work: ENOENT on connect()
- temporary output files are created in the curdir
- temporary output files are sometimes not erased
- socket file is created in the curdir

  definitions in smtlib-bv driver.
- Add no-bv.gen driver file targeted to provers without support for
  the smtlib bv theory (or for the no_bv variants).
- update realization & tests