Resolve "add basic argument handling"

Closes #1 (closed)

project1/bin/main.ml

 open Dolmen
-
 module M = Dimacs.Make(Std.Loc)(Std.Term)(Std.Statement)
 
-let () = print_endline "Hello, World!"
+let usage_msg = "project1 [--mode] ... [files]"
+let input_files = ref []
+let mode = ref "xor"
+let anon_fun filename =
+  input_files := filename :: !input_files
+let speclist =
+  [("--mode", Arg.Set_string mode, "Set working mode (xor or horn), default to xor");
+   ("-m", Arg.Set_string mode, "Set working mode (xor or horn), default to xor")]
+let () =
+  Arg.parse speclist anon_fun usage_msg;
+
+  List.iter print_endline !input_files;
+  print_endline !mode;