Temporarily cache notifications
EDIT  

Notifications Off is an android app available in play store, it will help you to make profiles so that you can block Some/All app notifications.  

ROOT is required for the app to work. 



There is feature called "Quiet hours" in CM 10.1 .  

It's available for your Nexus 7. Just install that ROM and set a time interval.
During that time period you can mute notifications, notification light and disable vibrations.

Settings-->Sound-->Quiet Hours

OR 

If you prefer to use ASOP, you can uncheck the Show Notification option in Apps info.