Add LICENSE to tarball.

[ralphbean]

The license file states that:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

... which means that, in order to be compliant with its own license, the tarball shipped to pypi needs to include the LICENSE file too.

It's easy to do! You must add include LICENSE to a file called MANIFEST.in and it should show up in the next tarball there.

[Anorov]

Done.