Refinement code requires private types to reside in
separate program declarations. So we split type decls
into chunks where all non-free types are declared
separately and only constructible (Ddata) types are
kept together. The code preserves the original order
wherever possible.

Also, export ls_of_rs and fd_of_rs from Expr: these are
used everywhere in src/mlw anyway.

Also, remove some range/float-related "assert false".

Somes experiments around the generation of type invariants implication.

Treatment of ghost branchs

Optional and named arguments

Optional and named arguments in functions signature.
For optional/named arguments in application it requires some more
work around the printer.

Avoid inlining proxy variables whenever there are conflicting effects

Not inlining proxy variables inside a [Efun].

Extraction of let x = e1 in e2

Optimization of proxy variables.

Why3 files from standard library are not extracted

Optimization of singleton record types.
Still missing treatment of record types defined in drivers

Empty extracted modules (all definitions are defined in the driver)
are printed no more, independently of the extraction mode

New command line nearly done

Preparing for the new command line.

Preparing for the new command line (flat recursive extraction of symbols
only works for definitions in the same file).

Preparing for the new command line (not working for now).

Preparing for the new command line.

Preparing for monolithic extraction.

Better treatment of partial applied constructors

in preparation of command-line option --mono

Support for recursive extraction and qualified names

Treatment of top-level constants