pptx: Select layouts from reference doc by name

Until now, users had to make sure that their reference doc contains
layouts in a specific order: the first four layouts in the file had to
have a specific structure, or else pandoc would error (or sometimes
successfully produce a pptx file, which PowerPoint would then fail to
open).

This commit changes the layout selection to use the layout names rather
than order: users must make sure their reference doc contains four
layouts with specific names, and if a layout with the right name isn’t
found pandoc will output a warning and use the corresponding layout from
the default reference doc as a fallback.

I believe the use of names rather than order will be clearer to users,
and the clearer errors will help them troubleshoot when things go wrong.

- Add tests for moved layouts
- Add tests for deleted layouts
- Add newly included layouts to slideMaster1.xml to fix tests

1 files changed, 0 insertions, 0 deletions

diff --git a/test/pptx/remove_empty_slides_deleted_layouts.pptx b/test/pptx/remove_empty_slides_deleted_layouts.pptx
new file mode 100644
index 000000000..7ae4a5fab
--- /dev/null
+++ b/test/pptx/remove_empty_slides_deleted_layouts.pptx