Update copyright

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
diff --git a/squashfs-tools/sort.c b/squashfs-tools/sort.c
index 2c3c721..f0dadac 100644
--- a/squashfs-tools/sort.c
+++ b/squashfs-tools/sort.c
@@ -2,7 +2,8 @@
  * Create a squashfs filesystem.  This is a highly compressed read only
  * filesystem.
  *
- * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012,
+ * 2013
  * Phillip Lougher <phillip@squashfs.org.uk>
  *
  * This program is free software; you can redistribute it and/or