Way to get a "recent apps" button back for easy quitting of apps running in background?

I just got the Virgin Mobile Supreme (also known as ZTE Supreme) and this phone has Android 4.1.2. The phone has only three hardware buttons: Back, Home and Options. My last phone had 4.0.4 and had four hardware buttons: Back, Home, Recent Apps, and Options. I am missing that button to view (and quit) recent apps.

Is there a way on this new phone to quickly access the apps running in the background so I can swipe them away and close them? My new phone does have something called Mi-POP, which has those four buttons float on the screen for me and I can access the running apps thing. But I would like a dedicated button to do this, maybe something I can put in the dock at the bottom of the screen where the dailer and apps menu button is. Mi-POP gets in the way. Any recommendations?

Old phone:


I am missing that third hardware button!

New phone:


Mi-POP, which kind of gets in the way and I can't leave it on all the time: