Since Magento CE 1.9.1 all “new order emails” are queued. A new defined cronjob
core_email_queue_send_all is now processing the queued emails.
During development it’s not very handy to run the job by a minute based scheduler. In this case you can use n98-magerun to start the cronjob manually.
$> n98-magerun.phar sys:cron:run core_email_queue_send_all