Add common printing functions

misc/utils.ml

+let string_of_formatter pp t =
+  Format.fprintf Format.str_formatter "%a" pp t;
+  Format.flush_str_formatter ()
+
+let pp_list ?(delim=("[","]")) ?(sep=",") f ppf l =
+  let rec aux ppf = function
+    |[] -> Format.fprintf ppf ""
+    |[h] -> Format.fprintf ppf "%a" f h
+    |h::t -> Format.fprintf ppf "%a%s%a" f h sep aux t
+  in
+  match l with
+    |[] -> Format.fprintf ppf "%s%s" (fst delim) (snd delim)
+    |_ -> Format.fprintf ppf "%s%a%s" (fst delim) aux l (snd delim)
+