Issue 403 - add Excel fetcher.

[mjordan]

Github issue: #403

What does this Pull Request do?

Adds a fetcher capable of reading Excel (.xlsx) files. This fetcher is a drop-in replacement for the Csv fetcher in Csv toolchains.

What's new?

• Added "box/spout":"*" to composer.json
• Added src/fetchers/Excel.php class file
• Updated src/metadataparsers/mods/CsvToMods.php to use fetcher configured in .ini file instead of hard-coded 'Csv' fetcher class.
• Added PHP unit tests for this new fetcher, plus an input file to use in the tests (tests/assets/excel/sample_metadata.xlsx)
• Modified other Csv test files to explicitly use the Csv fetcher class.

How should this be tested?

This change is testable. To test:

1. Check out the issue-403 branch.
2. Run composer update or equivalent on your system.
3. Run the PHPUnit tests: phpunit --exclude-group inputvalidators --bootstrap vendor/autoload.php tests. You should get 49 tests, 69 assertions.
4. When you check out master branch again, you probably should rerun composer update.

Additional Notes

We'll need to document the new Excel fetcher. Consistent with #372 and #373, I'm thinking something like https://github.com/MarcusBarnes/mik/wiki/Cookbook:-Templated-Metadata-Parser plus a mention in all the Csv toolchain wiki pages as an allowed option for [FETCHER] class. Draft is at https://github.com/MarcusBarnes/mik/wiki/Cookbook:-Using-the-Excel-fetcher (toolchain docs not updated yet).

I've tested this new fetcher on Linux and Windows with CsvToMods and Templated metadata parsers, and appears to work as intended.

Interested parties

@MarcusBarnes

@whikloj this is an example of the 'testable' workflow I mentioned in #402.

[MarcusBarnes]

Looks good. Running PHPUnit locally, I got OK (49 tests, 69 assertions) as expected. Thank you @mjordan.

[mjordan]

Thanks for testing, having this in master will make work on #408 a lot easier.