Cockroach REPL

[plaflamme]

Provide a REPL for interacting with cockroach cluster(s).

• consider that Client is asynchronous and you generally want to block in a REPL
• consider that a REPL can't really deal with byte arrays (use Base64 and converters to String and such)
• consider that it might be useful to connect to multiple clusters from a single REPL

scroach> val cluster = connect "cockroach-node:8080"
cluster: ReplClient
scroach> import cluster._
import cluster._
scroach> get("Hello")
res0: Base64 = b64(V29ybGQh)
scorach> res0.decodeUtf8
res1: String = "World!"