Immediate notifications disabled

This issue also concerns the Notifications and Subscriptions module, will submit this to those project as well.

The "immediate sending" option in Notifications module (see Clipboard01.png) allows the notifications to execute right away. But with Ajax, this doesn't work, and notifications aren't sent until the next cron. Moreover, in some cases the cron for subscriptions/notifications also fails (I wasn't able to identify when/how/why).