Once negated, consider the conjunctive normal form (CNF) of the goal if it is
not printable as is. This prevents failures on formula which are OK besides
their form. Indeed, CNF is logically equivalent to the original formula.

- Update to new stdlib organization.
- All properties in a single file, with formulation closer to the original.

- Add support for neural network as array in language.ml
- Translate csv record as vnnlib constraints in dataset.ml
- Add simple dataset normalization functionalities in dataset.ml
- Add vnnlib printer (as smtlib printer with direct real support)
- Add vnnlib driver for PyRAT
- Rework onnx and nnet parsers to not fail on non-mandatory information