streamline writeMatrix function

void DynamicalMatrix::writeMatrix(double **dynmat)

{

    if (me != 0 || fp == NULL) return;

    if (me != 0 || !fp)

        return;

    // print file comment lines

    if (!binaryflag && fp) {

    clearerr(fp);

    if (binaryflag) {

        for (int i=0; i<3; i++)

            fwrite(dynmat[i], sizeof(double), dynlen, fp);

        if (ferror(fp))

            error->one(FLERR, "Error writing to binary file");

    } else {

        for (int i = 0; i < 3; i++) {

            for (bigint j = 0; j < dynlen; j++) {

                if ((j+1)%3==0) fprintf(fp, "%4.8f\n", dynmat[i][j]);

                else fprintf(fp, "%4.8f ",dynmat[i][j]);

            }

        }

    }

        if (ferror(fp))

            error->one(FLERR,"Error writing to file");

    if (binaryflag && fp) {

        clearerr(fp);

        for (int i=0; i<3; i++)

            fwrite(dynmat[i], sizeof(double), dynlen, fp);

        if (ferror(fp))

            error->one(FLERR, "Error writing to binary file");

    }

}