Adding comparison tests and dependency on redis-py

- version numbers are now tracking redis-py version support
- bump up mockredis version to 2.7.2
- working on develop branch
use StrictRedis instead of Redis
Test with with Redis Server when possibe

Compare results of gets (defined in test_configuration) when redispy
and a local redis server is available.

TODO:

 - naming needs to be improved
 - currently the configuration is set for a very limited set of
   operations
Adding comparison tests and dependency on redis-py

- version numbers are now tracking redis-py version support
- bump up mockredis version to 2.7.2
- working on develop branch
use StrictRedis instead of Redis
Test with with Redis Server when possibe

Compare results of gets (defined in test_configuration) when redispy
and a local redis server is available.

TODO:

 - naming needs to be improved
 - currently the configuration is set for a very limited set of
   operations
Merge branch 'develop' of github.com:locationlabs/mockredis into develop
Switch per-build versioning convention.

We switched to having Jenkins overwrite the value of the __build__
variable because that works better when a build installs another
source distribution.
Use bintrees to implement sorted sets.
Add stub functions for sorted sets
Revert use of bintrees; it's not a great fit.
Improve sorted set:

 - Keep sorted list of (score, member) pairs.
 - Keep dictionary of member to score

Still uses O(N) list insert and removal operations.
More Pythonic container interface.
Implement zadd.

Fix return value of insert() to match documentation.
Implement zcard
Implement ZINCRBY
Implement zrange
Implement zrem
Implement ZSCORE
Implement zrevrange