multi: add getnetworkinfo rpc.

[dnldd]

This requires PR #1522.

[davecgh]

This is producing incorrect results in terms of the local addresses:

The following is output from my local tests:

  "localaddresses": [
    {
      "address": "",
      "port": 0,
      "score": 0
    },
    {
      "address": "",
      "port": 0,
      "score": 0
    },
    {
      "address": "",
      "port": 0,
      "score": 0
    },
    {
      "address": "",
      "port": 0,
      "score": 0
    },
    {
      "address": "",
      "port": 0,
      "score": 0
    },
    ...

[davecgh]

Also, please don't forget to update the JSON-RPC API documentation to add the new method.

[davecgh]

Latest updates looks good and reports the information as expected.