Fixed the GroupedSubjectIterator when dealing with an empty iterator

If one of the subject iterators is empty, the GroupedSubjectIterator needs
to move to the next iterator, otherwise the iteration will be incomplete.
Decomposed Testwork testers from their dispatchers
Fixed wrong LICENSE block in some Testwork classes
Decomposed Testwork testers from their dispatchers
Added missing typehints to testers
Using control flow instead of boolean operator in the hookable testers
Merge pull request #430 from stof/fix_group_subject_iterator

Fixed the GroupedSubjectIterator when dealing with an empty iterator
Merge pull request #433 from Behat/optimization/testers-refactoring

Testers refactoring
Removed unneeded argument from testers
Removed left use block from the last commit
Updated README with quality service badges
Added scrutinizer config
Extracted Transliterator into the separate package
Updated scrutinizer config
Removed php_mess_detector/config section as @schmittjoh recommended
Scrutinizer ignores i18n.php during PHP Code Sniffer phase
Refactored AnnotatedContextReader
Refactored ConfigurationLoader
Simplified ConfigurationLoader even more
Fixed wrong method typehint introduced during refactoring