Changed timeout connection pool param in README
Changed timeout connection pool param in README

The README was referring to an `IdleTimeout` option that is now named `Timeout`
GoRethink/gorethink,brendanobrienesq/gorethink,dancannon/gorethink,GoRethink/gorethink,SKatiyar/gorethink,dancannon/gorethink,GoRethink/gorethink,dancannon/gorethink