Connection Pooling #17

Thinking about connection pooling on a cluster with multiple connections.

Good starting point would be: (thanks AtnNn)
https://github.com/dancannon/gorethink/blob/master/cluster.go

This issue will serve as the design notes / change log implementation details.

A change feed on r.db("rethinkdb").table("server_status") seems like a great place to get updates about the cluster and IP info for multiple connections.

The next question would be how would we expose the API on r. to for a connection pool?

Current Connection API: Single Connection:

var c = r.connection()
         .hostname("192.168.0.11")
         .port(28015)
         .timeout(60)
         .connect();

Proposed API for connection pooling:

//Example 1
var p = r.connectionPool()
         .seed("192.168.0.11", "192.168,0.12", )
         .port(28015)
         .connect();
//Example 2
var p = r.connection()
         .pool()
         .seed("192.168.0.11", "192.168,0.12")
         .port(28015)
         .connect();
//Example 3
var p = r.cluster()
         .seed("192.168.0.11", "192.168,0.12", )
         .port(28015)
         .connect();

Any thoughts @deontologician on how the Java API would expose a pooled connection configuration?