Rename Port to PortNumber

Current util.Port actually only represent a port number.
Renaming it to PortNumber, so that it matches what it actually reprsent.

- Updated javadoc
- Removed unnecessary hashCode calculation
- Hide default constructor from public

Change-Id: Ib26c746eaa27464356c4ca0abff6af5e321afc35
diff --git a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
index 3b06ec3..aeb0c33 100644
--- a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
@@ -49,7 +49,7 @@
 import net.onrc.onos.core.util.IPv4Net;
 import net.onrc.onos.core.util.IPv6;
 import net.onrc.onos.core.util.IPv6Net;
-import net.onrc.onos.core.util.Port;
+import net.onrc.onos.core.util.PortNumber;
 import net.onrc.onos.core.util.Switch;
 
 import com.esotericsoftware.kryo.Kryo;
@@ -182,7 +182,7 @@
         kryo.register(IPv6Net.class);
         kryo.register(byte[].class);
         kryo.register(MACAddress.class);
-        kryo.register(Port.class);
+        kryo.register(PortNumber.class);
         kryo.register(Switch.class);
         // kryo.register(SwitchPort.class);