The NewtonSolver has been subclassed to try to auto enforce the zero boundary central condition by modifying the residual vector and the gradient matrix. This is a work in progress
BREAKING CHANGE:
the polytrope module will be used as an initial guess to the solver. A skeleton of this has been imported from https://github.com/tboudreaux/FEMPolytrope
This module will need major updates still to handle 3D, proper boundary conditions, and to incorporate it with the rest of our meshing scheme