implement separate buffering of tag data and cluster table

src/pipeline.h

@@ -90,6 +90,11 @@ extern enum ec3_status ec3_pipeline_read_cluster(
 	size_t cluster_id,
 	size_t *nr_read);
 
+extern enum ec3_status ec3_pipeline_copy_all(
+	struct ec3_pipeline *dest,
+	struct cluster_table *clusters,
+	FILE *data);
+
 extern size_t ec3_get_cluster_size(unsigned int v);
 extern enum ec3_pipeline_stage_type_id
 ec3_get_pipeline_stage_for_encryption_func(unsigned int func);