Revert "Do not include tests in release distributions"

This should keep tests in sdists but out of bdists.

http://curl.haxx.se/mail/curlpython-2014-07/0003.html

This reverts commit 343f253c60940c91cb2108d557ecc25ff8fc10fd.
Test fixtures come with tests
Merge pull request #203 from p-push/reinstate-tests

Reinstate tests in sdists