Make PHP_CodeCoverage_Report_Crap4j::$threshold configurable

[SchulteMarkus]

CRAP as an additional metric is awesome.

For time being, the CRAPpy threshold is hard coded to 30 within PHPUnit. According to Crap4j faq, this is a point where you have to start refactoring your code. Well, but in a goode php-project, you might want to see even CRAPpy code with less CRAP than 30.

Please make this threshold configurable, for example via phpunit.xml.

Background is, CRAPpy methods with less than 30 CRAP-points get a crapLoad = 0 (PHP_CodeCoverage_Report_Crap4j::getCrapLoad()). I am using crap4j.xml within Jenkins and Crap4j Plugin, and a I want to have methods with CRAP >= 20 reported by this plugin.

[SchulteMarkus]

Thank you!