This is the main code folder for the PyMailGUI program.
ListWindows.py and ViewWindows.py implement the two main 
window types in the GUI.

PyMailGUI uses both standard library code, and code from 
other module packages from the book.  The latter are in 
the nested PP4E folder here in this standalone release.
Most of the email heavy lifting occurs in the mailtools
package in PP4E.Internet.Email.  

The launcher, a subdirectory called altconfigs in the book,
is one level up from this folder in this release, and uses 
a wholly different and simpler scheme than that in the book.