Fail the testing fast when the Redis server is unreachable
Follow the default type of containers as the version of runtime

In Python 2.x, default types are ByteString.
in Python 3.x, default types are UnicodeString.

types.String matches the default string type of the platform.
Make test_hash.py pass in Python 3.3
Make test_set.py pass in Python 3.3
Make test_list.py pass in Python 3.3
Fix a wrong comparison and saving a sorted set
Make test_sortedset.py pass in Python 3.3
Fix syntax errors and make test_threadlocal.py pass in Python 3.3