Minor tweaks from running php-cs-fixer

php-cs-fixer --verbose fix src
   1) Broadway/Bundle/BroadwayBundle/DependencyInjection/BroadwayExtension.php (trailing_spaces, extra_empty_lines)
   2) Broadway/Bundle/BroadwayBundle/Resources/config/saga/in_memory.xml (trailing_spaces)
   3) Broadway/Bundle/BroadwayBundle/Resources/config/saga.xml (trailing_spaces)
   4) Broadway/EventSourcing/EventSourcedEntityInterface.php (phpdoc_params)
   5) Broadway/EventSourcing/Testing/Scenario.php (new_with_braces)
   6) Broadway/EventStore/EventStoreInterface.php (phpdoc_params)
   7) Broadway/Repository/AggregateNotFoundException.php (phpdoc_params)
   8) Broadway/Saga/MultipleSagaManager.php (unused_use)
Merge pull request #60 from mbadolato/php-cs-fixer_tweaks

Minor tweaks from running php-cs-fixer