proper handling of stateless nodes and automata

src/backends/C/c_backend_spec.ml

src/checks/stateless.ml

src/compiler_common.ml

src/compiler_common.mli

src/corelang.ml

src/corelang.mli

src/lustre_types.ml

src/lustre_types.mli

src/machine_code.ml

src/machine_code_common.ml

src/optimize_machine.ml

src/printers.ml

src/spec_common.ml

src/spec_common.mli

src/spec_types.ml

src/spec_types.mli