add SETNX function
add SETEX function
Merge pull request #3 from tumb1er/setex

add SETEX function
fix zscore for (nil)
remove key in tests just to be sure
spacing
Merge pull request #4 from tumb1er/zscore_nil

bugfix: zscore nil handling
Handle connection closed.
Renamed base exception.
Moved __doc__ to __init__.py
Merged setnx from tumb1er
Throw NoAvailableConnectionsInPool error when there are no established connections in the pool.
Updated docs index page.
Removed unnecessary asyncio.Task call.
__repr__ added to replies.
Removed pdb statements.
docs.
Typo in docs.
Pubsub refactoring: better API, more consistent with the transaction API.
Added pubsub example applications.