As the project already is installed via composer, this command
could save a few keystrokes!
Besides that, is just one command for all OS, because will not be
needed to change slashes to backslashes in Windows.
*X (21 keystrokes): `./vendor/bin/phpunit`
Windows (21 keystrokes): `.\vendor\bin\phpunit`
New (14 keystrokes): `composer test`
https://getcomposer.org/doc/articles/scripts.md#writing-custom-commands
- Move "tests/phpunit.xml" to "phpunit.xml.dist"
- Update documentation and contributing documents
- Update Travis settings
- Add "phpunit.xml" in the Git ignore list