Sorry but without GPU the toolkit is rather limited
http://discourse.vfitoolkit.com/t/what-can-i-run-without-a-gpu-with-just-cpu/
This is because the toolkit uses an algorithm (pure discretization) which is easy and robust, but is very very slow on CPU, decent runtimes on GPU. Hence for more advanced features it is just not worthwhile coding them except for GPU as they would be un-usably slow.
[There is also the ‘divide and conquer’ algorithm now in some parts of toolkit, but the way it is implemented is also specifically just for GPU]