Add poc files

h_files-format/outline.mli

@@ -0,0 +1,20 @@
+
+type outline = outline_node Common2.tree2
+    and outline_node = {
+      stars : string;
+      title : string;
+      before_first_children : string list;
+    }
+
+
+
+val outline_default_regexp : string
+
+(* value for implicit root *)
+val root_title : string
+val root_stars : string
+val is_root_node : outline_node -> bool
+
+
+val parse_outline : ?outline_regexp:string -> Common.filename -> outline
+val write_outline : outline -> Common.filename -> unit