Update: Add a Seed.reset function

lib/sasacore/seed.ml

-(* Time-stamp: <modified the 20/05/2021 (at 09:23) by Erwan Jahier> *)
+(* Time-stamp: <modified the 21/05/2021 (at 17:18) by Erwan Jahier> *)
 
 let seed = ref None
 let replay_seed = ref false      
@@ -11,7 +11,7 @@ let set s =
   seed := Some s
 
 let seed_file_name label =
-  Printf.sprintf "sasa-%s.seed" label 
+  Printf.sprintf "sasa-%s.seed" label
 
 (* for --replay *)
 let reset_the_seed_to_last label =
@@ -28,6 +28,8 @@ let reset_the_seed_to_last label =
     flush stderr;
     false
 
+let reset () = seed := None
+
 let rec (get : string -> int) = 
   fun label ->
   match !seed with

lib/sasacore/seed.mli

-(* Time-stamp: <modified the 20/05/2021 (at 09:25) by Erwan Jahier> *)
+(* Time-stamp: <modified the 21/05/2021 (at 11:29) by Erwan Jahier> *)
 
 val set : int -> unit 
+val reset : unit -> unit 
 
 (** The string is used to create  a file name to save/restore the seed
    when the --replay option is used *)