Non-linear benchmark problems

A set of non-linear continuous safety verification problems (in the KeYmaera X format) on which one can test Pegasus within KeYmaera X can be obtained from:

https://raw.githubusercontent.com/LS-Lab/KeYmaeraX-projects/master/benchmarks/nonlinear.kyx.

Most of the current benchmark problems are non-linear and just under half are 2-dimensional.