Write an app that simulates a traffic light using a single button; the button is first red and says STOP. When the user clicks on the button, it becomes green and says GO; when the user clicks on the button again, it becomes yellow and says WAIT; when the user on the button again, it becomes red and says STOP, and so forth. The button cycles to the next colour and text and simulates running the traffic light. You should look at the documentation of the View class to figure out how to change the colour of a View by code. The button should be centred horizontally and vertically in the middle of the screen.