added formulation with Cauchy stress that depends on deformation gradient, it does not converge
added formulation with Cauchy stress that depends on deformation gradient, it does not converge

saikanth88/femus,FeMTTU/femus,giorgiobornia/femus,FeMTTU/femus,eaulisa/MyFEMuS,eaulisa/MyFEMuS,FeMTTU/femus,saikanth88/femus,giorgiobornia/femus,FeMTTU/femus,eaulisa/MyFEMuS,giorgiobornia/femus,saikanth88/femus,giorgiobornia/femus,saikanth88/femus