Fix javadoc:javadoc warnings

- Exclude org.openflow.* from generated javadoc
- Fix warnings

Change-Id: I47aefff15582c6eec05b864fb19613200d07df03
diff --git a/src/main/java/net/onrc/onos/apps/websocket/TopologyWebSocket.java b/src/main/java/net/onrc/onos/apps/websocket/TopologyWebSocket.java
index f706944..1a83b94 100644
--- a/src/main/java/net/onrc/onos/apps/websocket/TopologyWebSocket.java
+++ b/src/main/java/net/onrc/onos/apps/websocket/TopologyWebSocket.java
@@ -32,8 +32,8 @@
  * <p>
  * <ol>
  * <li> WebSocket Client opens a WebSocket connection to the corresponding
- *    @ServerEndpoint: an instance for this class is created, and method
- *    @OnOpen is called. </li>
+ *    {@literal @ServerEndpoint}: an instance for this class is created, and method
+ *    {@literal @OnOpen} is called. </li>
  * <li> If the client sends a text message: method @OnMessage for String
  *    argument is called. </li>
  * <li> If the client sends a binary message: method @OnMessage