merge memory alloc for lbfgs

public:

    MinSpinOSO_LBFGS(class LAMMPS *);

    ~MinSpinOSO_LBFGS() {}

    virtual ~MinSpinOSO_LBFGS();

    void init();

    void setup_style();

    int modify_param(int, char **);

private:

    // global and spin timesteps

    int nlocal_max;		// max value of nlocal (for size of lists)

    double dt;

    double dts;

    double *spvec;		// variables for atomic dof, as 1d vector

    double *fmvec;		// variables for atomic dof, as 1d vector

    double *g;  		// gradient vector

    double *g_cur;  	// current gradient vector

    double *g_old;  	// gradient vector at previous step

    double *p;  		// search direction vector

    double *p_s;  		// search direction vector

    double **ds;  		// change in rotation matrix between two iterations, da

    double **dy;        // change in gradients between two iterations, dg

    double *rho;        // estimation of curvature