Fix the /sbin shasum256 tester.
Consider making it an xt test Using subs.

Finish docs for the current state.

DONE: Have the /bin/nf-fonts-info script write four files 
in the current directory, but only if they are not
there already.

LATER:

Provide an extended numerical list for the many
other known core fonts.

Provide a routine to provide a font when given
a list of descriptors.
