Add Django contrib utility package with tests.

Additionally, update copyrights
Add Django/Zookeeper commit to changelog.
Attempt to fix random integration test failure.

Rather than waiting to find out if the node exists,
which can sometimes return true before the actual
node data is properly set, we test the data that the
Watcher sees as registered in Zookeeper.
Fix another random integration test failure.

If datanode._watcher.get() returns None, don't try
to check that value as if it were an array, instead
immediately return false.w
Merge pull request #34 from diranged/django_contrib

Add Django contrib utility package with tests.