Powerpoint writer tests: Test everything with template as well

Modify the PowerPoint tests to run all the tests with
template (--reference-doc) as well. Because there are so many
interlocking pieces, bugs can pop up in weird places when using
templates, since it changes how the writer builds its output
file.

For example, I recently discovered a bug in which speaker notes worked
fine and templating worked fine elsewhere, but templating with speaker
notes produced a file that would crash MS PowerPoint. That particular
bug was fixed, but this will forces us to check for that with each new
change.

0 files changed, 0 insertions, 0 deletions