Update PETSc SNES solver and add I/F for constraint variables.
Main changes are
- fixing of few things in the PETSc SNES nonlinear solver.
- adding interface for processes to constrain variables range.
Also copied few SmallDeformation tests to test the nonlinear solver.
- Feature description was added to the changelog
- Tests covering your feature were added? Partially
- Any new feature or behavior change was documented?