Design an Animal class.
 -use good programming practice
 -separate interface and implementation
 -animals have a height and weight
 -overload input and output
 -overload addition
 -Due Weds
 -Friday for Sandbox work
 -To hand in this assignment, print a script as usual, but also email all CPP and H files to me. Tutorial on Friday
 -Implement functions for both eating and sleeping. These functions can 
simply output the fact that this animal is eating or sleeping.