Improve "Remote Code Coverage" code

[aik099]

1. find a reason why PHPUNIT and SELENIUM words are being used in prepend.php and append.php
2. replace append.php with a function registered via register_shutdown_function (as in Codeception)
3. convert append.php/prepend.php/phpunit_coverage.php into regular namespaced class, that can be tested
4. here is nice example http://tech.vg.no/2014/01/21/generating-code-coverage-of-behat-tests/

[aik099]

Also the new RemoteCoverage statement should be moved to DIC.

[stof]

@aik099 the files have been converted to a class using register_shutdown_function 11 months ago. Is there anything left or can it be closed ?

[aik099]

That's what create 20% loss of code coverage. Code is written theoretically, but not 100% tested.