[NH] Put remote address in log entries

[Pivotal](https://www.pivotaltracker.com/story/show/76885572)

This adds the client's remote address to all log entries. Entries without a client have an empty `[]` which is a little odd but it didn't seem worth the hassle to get rid of that. It looks like

```
INFO  o.a.f.listener.nio.FtpLoggingFilter - [/0:0:0:0:0:0:0:1:64412] CREATED
INFO  o.a.f.listener.nio.FtpLoggingFilter - [/0:0:0:0:0:0:0:1:64412] OPENED
INFO  o.a.f.listener.nio.FtpLoggingFilter - [/0:0:0:0:0:0:0:1:64412] SENT: 220 Service ready for new user.
```