adding bool option to propagate beam to multislice method

            from pycuda.tools import clear_context_caches

            clear_context_caches()

    def build_potential_slices(self, slice_thickness):

        # find number of slices and atomic sites per slice

        self.slice_t = slice_thickness

            grid_1d = (int((shape_x * shape_y) / block_1d[0]), int(shape_z), 1)

            return block_1d, grid_1d

    def multislice(self, bandwidth=1/3, unified_mem=False, batch_size=256):

    def multislice(self, bandwidth=1/3, unified_mem=False, batch_size=256, transmit=True):

        """

        :param bandwidth:

                num_probes = np.int32(self.probe_positions[phase][batch].shape[0])

                self.print_debug('batch: %s' % format(batch))

                self.__propagate_beams(num_probes, batch, probe_d, propag_d, psi_k_d, norm_const, grid_steps_d, grid_range_d,

                                     self.probes[phase][batch], plan, ones_d, stream)

                                     self.probes[phase][batch], plan, ones_d, stream, transmit=transmit)

            # ctx.synchronize()

        # 4. clean-up

            for plan, probe_d, norm_const in zip(plans, probes_d, norm_consts):

    def __propagate_beams(self, num_probes, batch, psi_pos_d, propag_d, psi_k_d,

                        norm_const_d, grid_steps_d, grid_range_d,

                        psi_x_pos_pin, fft_plan_probe, ones_d, stream):

                        psi_x_pos_pin, fft_plan_probe, ones_d, stream, transmit=True):

        """

        :param batch:

        :param psi_pos_d:

        # 2. Propagate probes through atomic potential

        # ctx.synchronize()

        if transmit:

            for i in range(self.num_slices):

                # self.print_debug('Atomic potential slice #%d' % i)

                multwise_stack_func.prepared_async_call(grid_3d, block_3d, stream, psi_pos_d, self.pot_dev_ptr, num_probes, np.int32(i),