Implement Redis protocol

[adamfowleruk]

[Who] As a user/programmer trying out GroundUpDB for the first time
[What] I want to be able to use exist Redis based API and apps to test GroundUpDB performance and functionality
[Value] In order to minimise my development and integration effort, allowing me to evaluate GroundUpDB quicker

Solution: Implement a basic (single threaded for now) redis TCP listener server. This will also require a long running server process main for ground up db, and not just an 'embedded' database approach.

References: Redis protocol described here: https://redis.io/topics/protocol

Acceptance: When I can execute the redis-benchmark tool against GroundUpDB for SET and GET operations with a single client connection.