Add references

Author: mattwynne

testdata/README.md

@@ -1,8 +1,8 @@
 # Acceptance test data
 
-The junit xml formatter uses the examples from the cucumber compatibility kit
+The junit xml formatter uses the examples from the [cucumber compatibility kit](https://github.com/cucumber/compatibility-kit)
 for acceptance testing. These examples consist of `.ndjson` files created by
-the `fake-cucumber` reference implementation. 
+the [`fake-cucumber` reference implementation](https://github.com/cucumber/fake-cucumber).
 
 * The `.njdon` files are copied in by running `npm install`.
 * The expected `.xml` files are created by running the