Add charset argument to Connection constructor.

Add possibility to configure charset option of RedisProtocol in the
Connection constructor.
Useful if you want to use Connection for binary data.
Added charset argument to all Connection methods. Updated docs.
Merge pull request #53 from ioga/connection-charset

Add charset argument to Connection constructor.
added password auth handling to the connection object to handle pooled connections and re-connections
removed incorrect description of what happens for incorrect auth details
added password argument to docs
Merge pull request #54 from tommyvn/master

Added password auth
ensure tests run against the local txredisapi
added support for pipelining
Merge pull request #56 from mjpizz/master

Added support for pipelining
make sure the values returned by execute_pipeline mirror the actual values from the redis commands
documented pipelining in the README
use fireOnOneErrback and consumeErrors in execute_pipeline
Merge pull request #57 from mjpizz/master

Fixed return values for execute_pipeline, and pipelining documentation
Removed python 2.5