Changed repo structure for proper install and tests

cpopen.so used to be installed in site-packages instead of
site-packages/cpopen. This patch fixes that by making
cpopen.so part of the cpopen package.

It also moves the tests into their own directory for better
organization.

Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Merge pull request #10 from celebdor/master

Changed repo structure for proper install and tests