Move the library to LGPLv2.1

This is a partial fix for #26. The tables are still licensed under
LGPLv3. What that means in legal terms I leave up to the layers. We will
have to go through the list of contributors again and figure out which
tables can change their license and which ones can't.
diff --git a/python/setup.py b/python/setup.py
index ef028ce..217b7f5 100644
--- a/python/setup.py
+++ b/python/setup.py
@@ -1,22 +1,23 @@
 # Liblouis Python ctypes bindings
 #
-#  Copyright (C) 2009 Eitan Isaacson <eitan@ascender.com>
-#  Copyright (C) 2010 James Teh <jamie@jantrid.net>
+# Copyright (C) 2009 Eitan Isaacson <eitan@ascender.com>
+# Copyright (C) 2010 James Teh <jamie@jantrid.net>
 #
-# This library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Library General Public
-# License as published by the Free Software Foundation; either
-# version 2 of the License, or (at your option) any later version.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# Library General Public License for more details.
-#
-# You should have received a copy of the GNU Library General Public
-# License along with this library; if not, write to the
-# Free Software Foundation, Inc., Franklin Street, Fifth Floor,
-# Boston MA  02110-1301 USA.
+# This file is part of liblouis.
+# 
+# liblouis is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published
+# by the Free Software Foundation, either version 2.1 of the License, or
+# (at your option) any later version.
+# 
+# liblouis is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+# 
+# You should have received a copy of the GNU Lesser General Public
+# License along with liblouis. If not, see <http://www.gnu.org/licenses/>.
+# 
 
 r"""Python bindings for liblouis
 """