I put all of our current work together, and added a virtual destructor
to Number.h.  All current errors are due to lack of an Irrational class.
I put all our work together and made minor changes.  All current errors
due to lack of irrational class.
All our stuff together.
Merge branch 'master' of https://github.com/NGoldfarb/Calculator.git

Conflicts:
	Calculator/main.cpp