use different exit codes in Functoria_runtime.with_argv (the command …

…line

processor):
- on parse failure, 64
- if help or version was requested, 65

reasoning is to design reasonable restart-on-failure semantics, unhandled OCaml
exceptions return 2 (from 4.10 on they'll instead abort() - 255 in solo5), solo5
failure use 1. i chose the space 64..70 arbitrarily for "never restart" in
albatross (but am open for discussion about any other range).

runtime/functoria_runtime.ml

@@ -80,5 +80,5 @@ let with_argv keys s argv =
     let t = List.fold_right gather keys (Term.pure ()) in
     match Term.(eval ~argv (t, info s)) with
     | `Ok _ -> initialized := true; ()
-    | `Error _ -> failwith "Key initialization failed"
-    | `Help | `Version -> exit 0
+    | `Error _ -> print_endline "Key initialization failed"; exit 64
+    | `Help | `Version -> exit 65