Merge branch 'CheHao' into 'master'

src/GUI/DrawingArea.java

src/GUI/MenuBar.java

src/GUI/ToolBar.java

src/client/Client.java

src/client/Client2.java

src/client/ClientCanvas.java

src/client/DrawingArea.java

src/client/PaintGUI.java

src/client/UpdateController.java

src/remote/IClientController.java

src/remote/IDrawingController.java

src/remote/IUpdateController.java

src/server/ClientController.java

src/server/DrawingController.java

src/server/Server.java

src/server/ServerDriver.java

src/server/User.java