[composer][phpcov] Rely to official packagist package
[composer] Upgrade to PHPUnit 4
Roll back to phpcov 1
#6029 - filtering code coverage managed paths
#6029 - requiring phpunit/phpcov ~2.0 (1.0.x had broken CLI tools)
#6029 - phpcov does not require `.php` suffix in cli tools
#6029 - phpunit should expect an exception only after checking whether the test should be skipped or not
#6029 - `CommonPatternTest` is abstract and should be extended, as `setUp` is expected to be overridden in subclasses
#6029 - no need for a `--whitelist` parameter for `phpcov`-cli
#6029 - `phpcov` command is called directly with `merge`, and not via parameter `--merge`
Merge pull request #6909 from Ocramius/update-phpcov-composer-reference

phpunit 4.x, phpcov 2.x (see #6029)