Attaching YANG model converter implementation.

Change-Id: I676639806903449ba86cf1858f4b28cfbb3a6eb7
diff --git a/apps/yang/src/main/java/org/onosproject/yang/YangRuntimeManager.java b/apps/yang/src/main/java/org/onosproject/yang/YangRuntimeManager.java
index 21fea28..a18a0af 100644
--- a/apps/yang/src/main/java/org/onosproject/yang/YangRuntimeManager.java
+++ b/apps/yang/src/main/java/org/onosproject/yang/YangRuntimeManager.java
@@ -40,6 +40,7 @@
 import org.onosproject.yang.runtime.YangRuntimeService;
 import org.onosproject.yang.runtime.YangSerializer;
 import org.onosproject.yang.runtime.YangSerializerRegistry;
+import org.onosproject.yang.runtime.impl.DefaultModelConverter;
 import org.onosproject.yang.runtime.impl.DefaultYangModelRegistry;
 import org.onosproject.yang.runtime.impl.DefaultYangRuntimeHandler;
 import org.onosproject.yang.runtime.impl.DefaultYangSerializerRegistry;
@@ -71,6 +72,7 @@
     private DefaultYangModelRegistry modelRegistry;
     private DefaultYangSerializerRegistry serializerRegistry;
     private DefaultYangRuntimeHandler runtimeService;
+    private DefaultModelConverter modelConverter;
 
     @Activate
     public void activate() {
@@ -81,6 +83,7 @@
                 new DefaultYangRuntimeHandler(serializerRegistry, modelRegistry);
         serializerRegistry.registerSerializer(new JsonSerializer());
         serializerRegistry.registerSerializer(new XmlSerializer());
+        modelConverter = new DefaultModelConverter(modelRegistry);
         log.info("Started");
     }
 
@@ -132,14 +135,12 @@
 
     @Override
     public ModelObjectData createModel(ResourceData resourceData) {
-        // TODO implementation.
-        return null;
+        return modelConverter.createModel(resourceData);
     }
 
     @Override
     public ResourceData createDataNode(ModelObjectData modelObjectData) {
-        // TODO implementation.
-        return null;
+        return modelConverter.createDataNode(modelObjectData);
     }
 
     @Override