Specialized tests for subsidiarity of mapfile edits.
Both greport and gsummary are tested, even though the code being
tested is in shared subroutines.


Part 1:  Subsidiarity

(Using more combinations than needed, so that we can reuse scaffolding
in Part 2.)

Precedence
	Internal-file over file

	Routine over file
	Routine over internal file

	line over file
	line over internal file
	line over routine
	
Edits
	V
	S
	I
	-

test.c is a single file with a single internal-file with a single
routine with a single line.

Part 2:  External edits

For each element in the matrix (g-tools.c), determine which of the
levels has an effect.
