In order for the contentreview module to send emails, you need to *either*:
* Setup the DailyTask script to run daily via cron. See framework/tasks/ScheduledTask.php for more information on setup.
* Install the queuedjobs module, and follow the configuration steps to create a cron job for that module. Once installed, you can just run dev/build to have a job created, which will run at 9am every day by default.