Significant changes in version 1.4:

- Many bugs were fixed in the sorted sets (redisZ*) functions.
- New unit tests for sorted set functions were added.

Significant changes in version 1.2:

1. We completely revamped communication with the Redis server, eliminating
   in-line messaging in anticipation of it's demise in future Redis versions.
   We also make a better effort to minimize copying by R prior to sending
   a message.

2. Added support for Redis hashes and ordered sets. The R/Redis client now
   fully supports all Redis types.
