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.
* Split Information functions into a dedicated class and namespace and categorise as Value or Error
* Refactor all error functions into the new ExcelError class
* Final breaking down the Engineering class for Excel Engineering functions into smaller individual/group classes
* Additional unhappy path tests for Complex Number functions
* Fix return docblocks for floats to allow for error strings
Adrien Crivelli
Mark Baker