How to disable the Lollipop notification popups while in a game? I know there are fixes for a rooted device  with Android 5.0+ to stop the notification popups for like text messages and apps like facebook. These I've found tend to be perminant and not so easy to do fixes so can't be used as a 'toggle' on / off.  

What I am looking for is some way that I can toggle off those notifications at the top of the screen that can interfere with seeing the screen or worse, if I'm drawing a picture it can totally damage the drawing by blocking where I'm working while I'm drawing and because I'm touching the screen there flips me out of the app I'm using and into the other app and sometimes even causes the original app to crash losing all the work.

By default, I have found NO built in option to turn these on or off. I like them when I'm just doing everything else and find them very useful so don't want them 'perma off'.

Anyone know of anyway or anything that may help with this? Is this hard coded in all editions of Lollipop?

EDIT: The model of phone in question is a T-Mobile Note 4 with Android 5.0.1. Model: SM-N910T. This is a rooted Stock rom.
I know of an app called Greenify that can hibernate apps to prevent notifications from popping up.

You can also simply tell it to hibernate with the screen on with the push of a button. Just open up the main screen and if any activities are awake that you want to hibernate, push the zzz button.