tentative implementation of DFSANESolver

Solver implementation from:

W. La Cruz, J. Martínez, and M. Raydan, “Spectral residual method without
gradient information for solving large-scale nonlinear systems of equations,”
Math. Comp., vol. 75, no. 255, pp. 1429–1448, 2006, doi:
10.1090/S0025-5718-06-01840-0.