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

instead of a function of type int->'a
a coercion is declared from arrays to sequences, so that notation a[i]
in the logic now refers to the sequence operation
small caveat: you have to open module seq.Seq to be able to use this
notation

updated the DTD accordingly, and all session files

- metas not there anymore
- lot of other simplifications
- sessions files updated accordingly when needed

a slightly different representation of coercions
(using trees instead of lists)
bench files for coercions

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