While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
* Not Finding Rels File
Fix#3553. Read of `\xl\worksheets\_rels\sheet1.xml.rels` fails on the new test worksheet (generated by 3rd party product), but read of `xl\worksheets\_rels\sheet1.xml.rels` (same name without leading slash) succeeds. I'm not sure why (over 400 tests succeed with the slash), so will probably delay this a bit while I do more research.
* Move Fix
Move to more logical place.