Fixed typos the first lines of some lisp files.

Reported by Levin Du.

lisp/org-agenda.el

@@ -1,4 +1,4 @@
-;;; org-agenda.el --- The table editor for Org-mode
+;;; org-agenda.el --- Dynamic task and appointment lists for Org
 
 ;; Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
 

lisp/org-colview-xemacs.el

@@ -1,4 +1,4 @@
-;;; org-colview.el --- Column View in Org-mode
+;;; org-colview-xemacs.el --- Column View in Org-mode, XEmacs-specific version
 
 ;; Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.