Add handler for HELLO websocket message

src/main/java/fi/flexplex/lib/FlexLibAdapter.java

@@ -2,6 +2,11 @@ package fi.flexplex.lib;
 
 public interface FlexLibAdapter {
 
+	/**
+	 * Called when WebSocket is connected and server responded HELLO
+	 */
+	public default void onWebSocketConnect() {} 
+
 	/**
 	 * Called when player friend list or friend requests are updated
 	 * @param player

src/main/java/fi/flexplex/lib/FlexLibAdapterImpl.java

@@ -14,4 +14,9 @@ public final class FlexLibAdapterImpl implements FlexLibAdapter {
 		this.flexLib.updatePlayerFriends(player);
 	}
 
+	@Override
+	public void onWebSocketConnect() {
+		this.flexLib.getLogger().info("WebSocket connected");
+	}
+
 }

src/main/java/fi/flexplex/lib/WebSocketClient.java

@@ -76,6 +76,10 @@ public final class WebSocketClient {
 								}
 							}
 							break;
+						case "HELLO":
+							for (final FlexLibAdapter listener : flexLib.getEventListeners()) {
+								listener.onWebSocketConnect();
+							}
 						default:
 							flexLib.getLogger().warning("Received invalid WebSocket message from FlexPlex. Message: " + args[0]);
 							break;