Retrieve a user

{
  "user": {
    "username": "admin",
    "firstName": "John",
    "lastName": "Doe",
    "email": "johndoe@example.com",
    "phone": "",
    "signature": null,
    "links": {
      "lists": "https://:account.api-us1.com/api/3/users/1/lists",
      "userGroup": "https://:account.api-us1.com/api/3/users/1/userGroup",
      "dealGroupTotals": "https://:account.api-us1.com/api/3/users/1/dealGroupTotals",
      "dealGroupUsers": "https://:account.api-us1.com/api/3/users/1/dealGroupUsers",
      "configs": "https://:account.api-us1.com/api/3/users/1/configs"
    },
    "id": "1"
  }
}