This is the top level of the Modules heirarchy.  Modules are
arranged by the following classifications:

	demo	Applications in demonstration mode
	eda	Electronic design automation
	math	Mathematics
	mcae	Mechanical computer aided engineering
	misc	Miscellaneous
	office	Office automation
	prog	Programming languages, libraries and systems
	unix	UNIX commands
	win	Window systems

A typical application will have a module referenced by
classification/application/version.  For example:
	office/wingz/1.1
