Support InetSocketAddress on RiakClient and RiakNode

Now, RiakClient and RiakNode can't handle different port number for each address. (ex. connect to 127.0.0.1:10018, 127.0.0.1:10028, 127.0.0.1:10038...) So, this PR allows the client to connect to such addresses.

I think the changes are helpful for the client's a failover test on local devrel environment, and more easy to setup RiakClient and RiakNode like this:


```java
RiakClient client = RiakClient.newClient(new InetSocketAddress("localhost", 8087),
    							new InetSocketAddress("localhost", 8187),
    							new InetSocketAddress("localhost", 8287),
    							new InetSocketAddress("localhost", 8387),
    							new InetSocketAddress("localhost", 8487));
```

It is my concern that I used variable argument parameter `String... addresses`. It seems different from the current coding style.

Any advice is helpful. thanks.