Licensing information was already present in README.md:

 - `numactl` and the demo programs are under the GNU General Public License, v.2.
 - `libnuma` is under the GNU Lesser General Public License, v2.1.

However, we weren't shipping a copy of the license text, so let's retify
that by including a copy of the text of both GPLv2 and LGPLv2.1.

Also update Makefile.am to include the LICENSE.* files in a dist tarball.

Signed-off-by: Filipe Brandenburger <filbranden@gmail.com>