(Experimental): implemented IPT composite images.

use LEX/YACC to parse IPT files.

Experimental/Artemis/IPT.Scanner.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace GameRes.Formats.Artemis
+{
+    internal partial class IPTScanner
+    {
+        void GetNumber()
+        {
+            yylval.n = int.Parse (yytext);
+            yylval.s = null;
+        }
+
+        void GetStringLiteral ()
+        {
+            yylval.s = yytext.Substring (1, yytext.Length-2);
+        }
+
+		public override void yyerror (string format, params object[] args)
+		{
+			base.yyerror (format, args);
+            if (args.Length > 0)
+                throw new YYParseException (string.Format (format, args));
+            else
+                throw new YYParseException (format);
+		}
+    }
+
+    public class YYParseException : Exception
+    {
+        public YYParseException (string message) : base (message)
+        {
+        }
+    }
+}