Adding Linking interfaces for Machines

* Refactoring of interface schema from yaml
* Adding linking to subnet for Machines
diff --git a/_modules/apiclient/maas_client.py b/_modules/apiclient/maas_client.py
index 530e6b2..6704597 100644
--- a/_modules/apiclient/maas_client.py
+++ b/_modules/apiclient/maas_client.py
@@ -242,4 +242,4 @@
         """Dispatch a DELETE on the resource at `path`."""
         url, headers, body = self._formulate_change(path, {})
         return self.dispatcher.dispatch_query(
-            url, method="DELETE", headers=headers)
+            url, method="DELETE", headers=headers, data=body)