enhanced rune.hawk with the string conversion feature

h2/lib2/h3-strings.adb

@@ -3,6 +3,17 @@ package body H3.Strings is
 	procedure Append (Obj: in out Elastic_String; V: in Rune_Array) is
 	begin
 		P.Append (P.Elastic_Array(Obj), V);
-	end;
+	end Append;
+
+	function Get_Rune (Obj: in Elastic_String; Pos: in System_Index) return Rune is
+	begin
+		return P.Get_Item(P.Elastic_Array(Obj), Pos);
+	end Get_Rune;
+
+	function To_Rune_Array (Obj: in Elastic_String) return Rune_Array is
+	begin
+		return P.To_Item_Array(P.Elastic_Array(Obj));
+	end To_Rune_Array;
+
 
 end H3.Strings;