Update all copyright dates.

svn path=/trunk/yasm/; revision=1827
diff --git a/libyasm.h b/libyasm.h
index b13abc2..ec92aa5 100644
--- a/libyasm.h
+++ b/libyasm.h
@@ -7,7 +7,7 @@
  * \endrcs
  *
  * \license
- *  Copyright (C) 2003  Peter Johnson
+ *  Copyright (C) 2003-2007  Peter Johnson
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions