Write a program called mydu that works like the linux utility du.  The minimal requirement is that mydu will print all the directories reachable from the current directory and the number of Kilobytes of storage used by each directory.  Study the api, particularly java.io.File for constructors and methods.  It will also be useful to study the code in the text book that prints all files and directories under the current directory on page 603.  Use the submit process and name the directory containing code proj4.