Moved FHIR API from "Health" to "Test Data" section

Per recommendation, moved this new link to "Test Data" section since data contained by the API is "dummy data" conforming to the FHIR spec.

README.md

@@ -363,7 +363,6 @@ API | Description | Auth | HTTPS | Link |
 |---|---|---|---|---|
 | BetterDoctor | Detailed information about doctors in your area | `apiKey` | Yes | [Go!](https://developer.betterdoctor.com/) |
 | Diabetes | Logging and retrieving diabetes information | No | No | [Go!](http://predictbgl.com/api/) |
-| FHIR | Fast Healthcare Interoperability Resources test data | No | Yes | [Go!](http://fhirtest.uhn.ca/home) |
 | Flutrack | Influenza-like symptoms with geotracking | No | No | [Go!](http://www.flutrack.org/) |
 | Healthcare.gov | Educational content about the US Health Insurance Marketplace | No | Yes | [Go!](https://www.healthcare.gov/developers/) |
 | Makeup | Makeup Information | No | No | [Go!](http://makeup-api.herokuapp.com/) |
@@ -594,6 +593,7 @@ API | Description | Auth | HTTPS | Link |
 |---|---|---|---|---|
 | Adorable Avatars | Generate random cartoon avatars | No | Yes | [Go!](http://avatars.adorable.io) |
 | Bacon Ipsum | A Meatier Lorem Ipsum Generator | No | Yes | [Go!](https://baconipsum.com/json-api/) |
+| FHIR | Fast Healthcare Interoperability Resources test data | No | Yes | [Go!](http://fhirtest.uhn.ca/home) |
 | Hipster Ipsum | Generates Hipster Ipsum text | No | No | [Go!](http://hipsterjesus.com/) |
 | JSONPlaceholder | Fake data for testing and prototyping | No | No | [Go!](http://jsonplaceholder.typicode.com/) |
 | Lorem Text | Generates Lorem Ipsum text | `X-Mashape-Key` | Yes | [Go!](https://market.mashape.com/montanaflynn/lorem-text-generator) |