4th order is mostly working with CircleSolver (homogeneous)
Part of the LU caching system
Caching system complete
Add compression to caching system
Make caching system optional since it doesn't work that well

It's currently disabled (hard-coded)
4th order scheme working for inhomogeneous equations
Remove Ellipsoid problem
Move grid plotting reference code
Remove caching system
Add util/gen_problem_code.py