Fixed #9

Example of output:
```
[20:24:37][giorgio@Bipbip:~/code/eris]$ vendor/bin/phpunit test/
PHPUnit 4.4.0 by Sebastian Bergmann.

Configuration read from /home/giorgio/code/eris/phpunit.xml

..F..........

Time: 1.05 seconds, Memory: 15.75Mb

There was 1 failure:

1) Eris\ExampleEnd2EndTest::testWhenTests
It appears the command
vendor/bin/phpunit --log-junit /tmp/phpunit_log_drT54X /home/giorgio/code/eris/examples/WhenTest.php
has crashed without leaving a log for us to analyze.
This was its output:
Fatal error: Call to undefined function cdsacdsa() in /home/giorgio/code/eris/examples/WhenTest.php on line 3

Call Stack:
    0.0002     236016   1. {main}() /home/giorgio/code/eris/vendor/phpunit/phpunit/phpunit:0
    0.0026     561792   2. PHPUnit_TextUI_Command::main() /home/giorgio/code/eris/vendor/phpunit/phpunit/phpunit:62
    0.0026     562424   3. PHPUnit_TextUI_Command->run() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/TextUI/Command.php:138
    0.0074    1225408   4. PHPUnit_Runner_BaseTestRunner->getTest() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/TextUI/Command.php:160
    0.0074    1225456   5. PHPUnit_Runner_BaseTestRunner->loadSuiteClass() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/Runner/BaseTestRunner.php:105
    0.0077    1249336   6. PHPUnit_Runner_StandardTestSuiteLoader->load() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/Runner/BaseTestRunner.php:160
    0.0077    1282280   7. PHPUnit_Util_Fileloader::checkAndLoad() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/Runner/StandardTestSuiteLoader.php:78
    0.0078    1282392   8. PHPUnit_Util_Fileloader::load() /home/giorgio/code/eris/vendor/phpunit/phpunit/src/Util/Fileloader.php:77
    0.0080    1323960   9. include_once('/home/giorgio/code/eris/examples/WhenTest.php') /home/giorgio/code/eris/vendor/phpunit/phpunit/src/Util/Fileloader.php:93

/home/giorgio/code/eris/test/Eris/ExampleEnd2EndTest.php:55
/home/giorgio/code/eris/test/Eris/ExampleEnd2EndTest.php:27
```