Adds automatic deletion of empty Connections & Links

src/main/java/de/tu_darmstadt/tk/SmartHomeNetworkSim/control/Controller.java

@@ -266,7 +266,13 @@ public class Controller {
 	 * @param link the Link, which contains the SmartDevice
 	 */
 	public void removeSmartDeviceFromLink(SmartDevice toRemove, Link link) {
-		link.removeDevice(toRemove);
+		if(link != null){
+			link.removeDevice(toRemove);
+			if(link.getDevices().size()==0)
+				deleteLink(link);
+		}
+		if(toRemove!=null)
+			toRemove.removeLink(link);
 	}
 	
 	/**
@@ -432,10 +438,20 @@ public class Controller {
 		}
 	}
 	
+	/**
+	 * Removes Device p from the Connection
+	 * @param p Port/Device to remove
+	 * @param connection connection, which should remove the device
+	 */
 	public void removeDeviceFromConnection(Port p, Connection connection){
-		connection.removeSmartDevice(p);
-		connection.getProtocol().removeDevice(p);
-		p.setConnection(null);
+		if(connection != null){
+			connection.removeSmartDevice(p);
+			connection.getProtocol().removeDevice(p);
+			if(connection.getParticipants().size() == 0)
+				deleteConnection(connection);
+		}
+		if(p!=null)
+			p.setConnection(null);
 	}
 	
 	/**
@@ -472,7 +488,6 @@ public class Controller {
 	 * @return true on successful change, false on failure & restore
 	 */
 	public boolean changeLinkOfConnection(Connection connection, Link newLink) {
-		// TODO Auto-generated method stub
 		if(newLink != null){
 			connection.getLink().removeConnection(connection);
 			connection.setLink(newLink);