PIE controls is a hidden soft buttons menu that you swipe in existence when you want to use one or any of them. I much prefer it over the dormant bar. It's been baked into mainline cm since last month,
here's how it looks like. So a long as very green used fresh cm sources it will be right there embedded in his new ROM as an option... I'm sorry I haven't installed his new version yet so I'm not sure if it is there or not so yo have to go there looking... If is not embedded then you'd have to disable the navigation bar manually, either -again- from a settings' option or by using an app called fullscreentoggle...
Lastly you can use gestures to go around using GMD gesture control, but be warned that it doesn't come free from the store. There is a gmd lite version lately but I haven't used it so I don't know how capable is it, it would be probably be best to try the free version first to see if it suits you... What GMD does pretty much is letting you assign multi finger gestures to simulate functions including the ones executed by the soft buttons...it also let's you use your screen's edges as buttons...