Tweak to Eugene Crosser's patch to make transactions and acks configurable; disabling...

Tweak to Eugene Crosser's patch to make transactions and acks configurable; disabling them gets basic message delivery working under MorbidQ, and may help with RabbitMQ etc.

I swapped the settings from negative to positive ($config['queue']['stomp_transactions'] = false rather than $config['queue']['stomp_no_transactions'] = true), gave them defaults (both on for best ActiveMQ experience), and added notes to the README about configuring them.