Added support for enabling Tunnel End-points as next-hop for reaching end-points in an

OF Cluster from a L3 NOF domain.
o VRS detects traffic destined to TEP's MAC and !TEP IP and applies the
  virtual routing logic to the device corresponding to dstIp. It marks the orig dst device
  in the floodlight context
o Forwarding checks for the orig dst device in floodlight ctxt being a TunnelEndPoint.
  If so, it ensures that the packet is received on the designated port for the TEP device and
  computes the route to the destination device as follows:
      o Intra Cluster SourceSwitch --> DestSwitch
      o Prepend {Source Switch,Port}
      o Append {Dest Switch,Port}
o Reconcile changes in VRS and Forwarding to handle such flows.
o Junit tests

src/main/java/net/floodlightcontroller/devicemanager/IDeviceService.java

@@ -51,6 +51,12 @@ public interface IDeviceService extends IFloodlightService {
     public static final String CONTEXT_DST_DEVICE = 
             "net.floodlightcontroller.devicemanager.dstDevice"; 
 
+    /**
+     * The original destination device for the current packet-in
+     */
+    public static final String CONTEXT_ORIG_DST_DEVICE =
+            "net.floodlightcontroller.devicemanager.origDstDevice";
+
     /**
      * A FloodlightContextStore object that can be used to interact with the 
      * FloodlightContext information created by BVS manager.