Bumping phpunit version in composer.json
Fixing strict standards in language feature tests
Fixing failure related with Zend\Code\Generator API misuse
Skipping tests for HHVM when closures are required

Depends on facebook/hhvm#1203
Allowing matching of 'HHVM Fatal Error' instead of just 'Fatal Error'
Lazier checks against fatal exceptions
Merge branch 'feature/phpunit-4'