[LaraPackagePort] Analyse for Laravel 5.5

[LKaemmerling]

This Pull-Requests help you to prepare your Package for Laravel 5.5. I've tested it automated and this was the PHPUnit Result:
PHPUnit 6.3-dev by Sebastian Bergmann and contributors.

Runtime: PHP 7.1.7 with Xdebug 2.5.5
Configuration: /Users/lukaskammerling/Code/OSS/spatieLaravelphp5.5/storage/spatie.laravel-tinker-tools/phpunit.xml.dist

E 1 / 1 (100%)

Time: 112 ms, Memory: 6.00MB

There was 1 error:

1. Spatie\TinkerTools\Test\ShortClassNamesTest::it_can_register_short_name_classes
   Error: Class 'NamespacedClass' not found

/Users/lukaskammerling/Code/OSS/spatieLaravelphp5.5/storage/spatie.laravel-tinker-tools/tests/ShortClassNamesTest.php:27

ERRORS!
Tests: 1, Assertions: 1, Errors: 1.

Generating code coverage report in Clover XML format ... done

Generating code coverage report in HTML format ... done

So there are some errors, but it could work!