Notes for Project 4:
1) Added April 23:

   Question: May I use Vectors to store data in nodes, instead of Lists?
   Answer (Edelman): If you use a data structure similar to the one
	  presented in class for BTreeNode, then you may use vectors
	  instead of dynamically allocated arrays for storing keys
	  and subtree (i.e. for the internal node) information. 
	  NOTE: you should still use the List ADT to store data values.

2) added April 23 (Frey)
   Project Modification: When you produce output, you must now also print
   the command as well as its output. 
   This is not only a good debugging technique, but it will assist
   all concerned in making your projects run correctly.