To run integration tests:
1. Replace 'describe.skip' with 'describe' in test/integration/integration-test.js
2. Create a file at ~/.ripple_wallet containing a JSON object like this with
   your own test address and secret.
    {
      "test": {
        "address": "r3GgMwvgvP8h4yVWvjH1dPZNvC37TjzBBE",
        "secret": "shsWGZcmZz6YsWWmcnpfr6fLTdtFV"
      }
    }
3. Run "mocha test/integration/integration-test.js"