Implement REST APIs for flows:

- get all flows
- get all flows for a device
- get all flows for a device with a given ID

Change-Id: Ifb1541e4ae4a7e49f1347b34bef2fe788902368d
diff --git a/web/api/src/main/java/org/onosproject/codec/impl/CodecManager.java b/web/api/src/main/java/org/onosproject/codec/impl/CodecManager.java
index 562cdc0..6980a34 100644
--- a/web/api/src/main/java/org/onosproject/codec/impl/CodecManager.java
+++ b/web/api/src/main/java/org/onosproject/codec/impl/CodecManager.java
@@ -29,6 +29,9 @@
 import org.onosproject.net.HostLocation;
 import org.onosproject.net.Link;
 import org.onosproject.net.Port;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.TrafficSelector;
+import org.onosproject.net.flow.TrafficTreatment;
 import org.onosproject.net.intent.Intent;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -59,6 +62,9 @@
         registerCodec(Host.class, new HostCodec());
         registerCodec(HostLocation.class, new HostLocationCodec());
         registerCodec(Intent.class, new IntentCodec());
+        registerCodec(FlowEntry.class, new FlowEntryCodec());
+        registerCodec(TrafficTreatment.class, new TrafficTreatmentCodec());
+        registerCodec(TrafficSelector.class, new TrafficSelectorCodec());
         log.info("Started");
     }