Add GPLv2+ license and copyright notice

smem

@@ -1,4 +1,13 @@
 #!/usr/bin/python
+#
+# smem - a tool for meaningful memory reporting
+#
+# Copyright 2008-2009 Matt Mackall <mpm@selenic.com>
+#
+# This software may be used and distributed according to the terms of
+# the GNU General Public License version 2 or later, incorporated
+# herein by reference.
+
 import re, os, sys, pwd, grp, optparse, errno, tarfile
 
 _ucache = {}