Remove pimple dependency

Pimple source and test added as suggested in #21 issue, then added `aik099` namespace prefix.

Files were just copied, so they adhere to Pimple coding standards. I see that phpunit-mink has got its own coding standards, but I don't know it nor how to check it. Please advise.

**Caveat**: test error that I can't find a way to fix or figure out what is wrong:
```
1) tests\aik099\PHPUnit\Integration\EventDispatchingTest::testSetupEvent
Mockery\Exception\InvalidCountException: Method stop() from Mockery_5_Behat_Mink_Session should be called
 exactly 2 times but called 0 times.
```