Adding ability to project device, link and host model as alternate entities.

Change-Id: If23c018b024a3bbe693f0e66888c5f1707e3f66d
diff --git a/core/api/src/main/java/org/onosproject/net/Element.java b/core/api/src/main/java/org/onosproject/net/Element.java
index 6cdab9e..b918ad9 100644
--- a/core/api/src/main/java/org/onosproject/net/Element.java
+++ b/core/api/src/main/java/org/onosproject/net/Element.java
@@ -15,10 +15,12 @@
  */
 package org.onosproject.net;
 
+import org.onosproject.net.driver.Projectable;
+
 /**
  * Base abstraction of a network element, i.e. an infrastructure device or an end-station host.
  */
-public interface Element extends Annotated, Provided {
+public interface Element extends Annotated, Provided, Projectable {
 
     /**
      * Returns the network element identifier.