While there is value in providing those, they also clutter IDE auto-complete feature.
Now they users can opt-in to download them via `--prefer-source` flag.
Closes#908Closes#1424
All code for unit tests is now under the `PhpSpreadsheet\Tests` namespace
which is autoloaded via composer mechanism. So there is no need for
`require()` anymore.
Also, tests were moved in `tests/` folder and phpunit should be executed from
the project root folder. This is to conform to the de facto standard, notably
in use in phpunit itself.
Added .gitattributes file to identify files/folders that should be excluded from a composer distribution unless invoked as
composer install --prefer-source
Adrien Crivelli