allow shape shape updates in bff

Unlike the original version in VoigtlaenderHMW13, we do not request an
  sput : ℕ → ℕ → Maybe ℕ
function for determining the updated source shape from the original
source and updated view shape. Instead we ask the caller directly to
provide the result of sput together with a proof that its getlen matches
with the provided, updated view.

The precondition assoc-enough is not enriched in this way and still
requires a non-changing shape. I.e. it says what it said before.

0 files changed, 0 insertions, 0 deletions