suanPan v1.7 Release Notes

    1. revise SimpleSand model
    2. add DafaliasManzari sand model โœ… 5. add materialtestbystrainhistory and materialtestbystresshistory utility functions ๐Ÿ›  6. bugfix: potential racing in initialising reference dof, change to serial initialisation ๐Ÿ›  7. bugfix: wrong update of plastic strain in CDP model
    3. add CDPM2 model with isotropic damage