No code changes. The tests in all of these scripts write to at least
one temporary file, which is then read and not used again. The file
should be deleted to avoid filling up the disk system.
CALCULATION_REGEXP_CELLREF is not sufficiently robust.
It treats some perfectly legal defined names, e.g. A1A, as cell refs.
When the Xlsx Writer tries to save a worksheet which uses such a name
in a formula in a cell, it throws an exception.
The new DefinedNameConfusedForCellTest is a simple demonstration.
The Regexp has been changed to ensure the name starts on a Word boundary,
and to make sure it is not followed by a word character or period.
This fixes the problem, and does not appear to cause any regression
problems in the test suite.
Closes#1263