Convert protocol response to Redis format

Protocol as defined at:
http://redis.io/topics/protocol

Erlang integers get returned as Redis integers.
Erlang binaries get returned as Redis bulk strings.
Erlang atoms null and undefined get returned as Redis Null.
Other Erlang atoms get returned as upper-cased Redis simple strings.
Erlang lists get convereted to Redis Arrays. (nested lists work too)

Tests added for basic protocol generation.

All tests pass.