Switch to LGPLv2+ for most code

Since we're making a shared library, it should be usable by non-GPL
apps.

To allow more code sharing between the core and the tests, move them
to the LGPLv2+ too.

A few bits of test and other code are still GPL.  See the new COPYING
file for more information.

tests/Makefile

@@ -2,21 +2,20 @@
 #
 # Copyright (C) 2011 Colin Walters <walters@verbum.org>
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU 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 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 of the License, or (at your option) any later version.
 #
-# This program is distributed in the hope that it will be useful,
+# 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 General Public License for more details.
+# 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 General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-#
-# Author: Colin Walters <walters@verbum.org>
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
 
 TESTS = $(wildcard t[0-9][0-9][0-9][0-9]-*.sh)