Critical for stability mapping

Also, use the local git checkout instead of downloading a source tarball from
the website.

Under Debian 12, it fails with:
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/12/libgomp.a(team.o): réadressage R_X86_64_TPOFF32 vers symbole caché « gomp_tls_data » ne peut pas être utilisé en créant un objet partagé

GSA_recursive: make sure nobs is correctly set before checking for recursive estimation

Closes #1611

See merge request Dynare/dynare!2269

Closes #1611

Closes: #1707

This workaround was implemented in cd195279.
The zero-width spaces were inadvertently removed in
248ad188.

Ref. #1707

Ref. !2268

Ref. !2267

Ref. !2266

Ref. !2263

Ref. !2261

OccBin tools: rework codes

See merge request Dynare/dynare!2251

Ref. !2265

Ref. !2264

Ref. !2262

required for some symbols users regularly use

preprocessor increments lags/leads always only by lead_lag

transformed steady state is not passed back anymore

Ref. !2256

The implicit conversion from Vector to ConstVector, in addition to the
rewriting rules and ConstVector::operator<=>, ensure that those are no longer
needed.

Those are no longer needed thanks to expression rewriting.

Prevents warnings if relative difference involves division by almost 0

Ref. !2260

Also minor improvements to solve_algo description.