Add 3 examples for State pattern using PHPUnit and Composer

Completely rewrote the state example with Car colors, see it and let me know what you think. Besides I wrote 2 more examples of State pattern usage. All in TDD fashion (used PHPUnit and Composer).

To run the tests install Composer and execute following:

```
cd state/php
composer install
vendor/bin/phpunit test/car_example_test.php
vendor/bin/phpunit test/turnstile_example_test.php
vendor/bin/phpunit test/delivery_example_test.php
```

Let me know what you think, we have some new stuff here that we may want to rethink before we take a direction on so feedback is important.