Write  Java GUI apps.

1. Create a input box and a button.  The user enters a number to the input box,
then clicks the button. A random integer between 0 and floor(number) is outputted
to console.

2. Create an input box and a button. The user enters a number to the input box,
then clicks the button. A random integer between 0 and floor(number) is outputted
to the GUI.

3. Create two input boxes and a button. The user enters values to the boxes, then
clicks the button. The average of the two numbers is outputted to the GUI.

4. Create two input boxes and four buttons. The user enters values to the boxes.
If the first button is clicked, then the numbers added together is outputted. 
If the second button is clicked, then the numbers subtracted is outputted.
If the third button is clicked, then the numbers multiplied together is outputted. 
If the fourth button is clicked, then the numbers divided is outputted.

5. Draw 10 circles of random sizes, locations and colors on the GUI.

6. Draw 10 circles and rectangles of random sizes, locations and colors on the 
GUI. The choice of circle or rectangle is also random.