Replace use of "global" variables with "module level" variables

Brad expressed modest dismay that the Spec contains the phrase "Global" variables
rather than "Module level" variables.  I have performed a global replace, no pun intended,
to address this.

This may be a poor time to make this change in which case I will cheerfully delete this branch
and revisit in the next cycle.

In this context, maybe it would be better to name the module in which these variables are declared.