Warn the user if they use both a default and `timescale based delay.

This patch add code to print a warning message if it finds both a
default and `timescale based delays. The -Wall or more specifically
the -Wtimescale flag can be used to find the module with the missing
`timescale directive.

Module.h

@@ -1,7 +1,7 @@
 #ifndef __Module_H
 #define __Module_H
 /*
- * Copyright (c) 1998-2008 Stephen Williams ([email protected])
+ * Copyright (c) 1998-2009 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -105,6 +105,7 @@ class Module : public PScope, public LineInfo {
 	/* These are the timescale for this module. The default is
 	   set by the `timescale directive. */
       int time_unit, time_precision;
+      bool time_from_timescale;
 
 	/* Task definitions within this module */
       map<perm_string,PTask*> tasks;