Changing World Nomad logo to most recent one provided.

> **Trello ticket:** https://trello.com/c/LvKydigy/368-insurance-change-logo-world-nomads

Just updating the logo to the one provided in the Dropbox folder that's specified in the ticket above.

![world-nomads](https://cloud.githubusercontent.com/assets/7049277/5478894/c076e60a-85fd-11e4-9e70-6c5d533a1ff7.png)