Add a more readable #inspect

Before this change, it's a huge text dump because it shows all sorts of stuff including the datastore and instance vars of the associated module.

```
15:06:37 0 0 exploit(java_signed_applet) > exploit
[*] Exploit running as background job.
15:06:39 1 0 exploit(java_signed_applet) >
[*] Started reverse handler on 0.0.0.0:4444
[*] Using URL: http://0.0.0.0:8080/
[*]  Local IP: http://10.6.0.86:8080/
[*] Server started.
   
15:06:40 1 0 exploit(java_signed_applet) > irb
[*] Starting IRB shell...
   
Loaded ~/.irbrc
>> framework.jobs.values.first.ctx.first.send :service
=> #<Rex::Proto::Http::Server http://0.0.0.0:8080 [ "/" ]>
```

Now it's nice and pretty.