Merge branch 'update/blanchard/wp/why3' into 'master'

nix/alt-ergo.nix

nix/ocplib-simplex.nix

nix/pkgs.nix

nix/sources.json

opam

reference-configuration.md

src/plugins/wp/Stats.ml

src/plugins/wp/VCS.ml

src/plugins/wp/VCS.mli

src/plugins/wp/Why3Provers.ml

src/plugins/wp/doc/manual/wp_plugin.tex

src/plugins/wp/share/why3/frama_c_wp/cbits.mlw

src/plugins/wp/share/why3/frama_c_wp/vset.mlw

src/plugins/wp/tests/qualif.report

src/plugins/wp/tests/why3/test_config_qualif

src/plugins/wp/tests/wp/oracle/sharing.res.oracle

src/plugins/wp/tests/wp/oracle/wp_eqb.res.oracle

src/plugins/wp/tests/wp_acsl/chunk_typing_usable.i

src/plugins/wp/tests/wp_acsl/classify_float.c

src/plugins/wp/tests/wp_acsl/div_mod.i