COXInteger class
 This demo will convert a number from one radix to another or to a string representation.  

A COXInteger object encapsulates a (large) possible negative integer. The internal representation is decimal huge integer (LONGLONG == _int64).
An object can be constructed from a decimal number or the text representation expressed in a specified radix.

Features:
•	COXInteger represents a (large) integer 
•	It uses minimal memory (only one non-static data member) 
•	It can produce and accept numbers represented in a specified radix 
•	It can thousand separate digits within a number 
•	Supports negative numbers 
•	Has constructor that accepts a number and a conversion operator that produces the number