1、增加Maat_command_raw_set_xx系列函数，可以操作sub-group、分组复用，增加sub-group增删的测试用例。 2、fix #13。

test/test_igraph.cpp

@@ -0,0 +1,62 @@
+#include "igraph/igraph.h"
+#include <assert.h>
+
+void print_vector(igraph_vector_t *v, FILE *f) {
+  long int i;
+  for (i=0; i<igraph_vector_size(v); i++) {
+    fprintf(f, " %li", (long int) VECTOR(*v)[i]);
+  }
+  fprintf(f, "\n");
+}
+
+int main() {
+
+	igraph_t g;
+	int ret;
+	ret=igraph_empty(&g, 0, IGRAPH_DIRECTED);
+
+	igraph_es_t es;
+	igraph_integer_t edge_num_before=0, edge_num_after=0;
+	int v[10];
+	int i=0;
+	for(i=0; i<sizeof(v)/sizeof(int); i++)
+	{
+		v[i]=i;
+		igraph_add_vertices(&g, 1, NULL);	//Add 1 vertice.
+	}
+	igraph_add_edge(&g, v[0], v[1]);
+	igraph_add_edge(&g, v[0], v[1]);
+
+	igraph_add_edge(&g, v[2], v[3]);
+
+	int edge_id=0;
+	ret=igraph_get_eid(&g, &edge_id, v[2], v[3], IGRAPH_DIRECTED, 0);
+	assert(edge_id>0);
+
+	ret=igraph_es_pairs_small(&es, IGRAPH_DIRECTED, v[0], v[1], -1);
+	assert(ret==IGRAPH_SUCCESS);
+	edge_num_before=igraph_ecount(&g);
+	ret=igraph_delete_edges(&g, es);
+	edge_num_after=igraph_ecount(&g);
+	assert(edge_num_before-edge_num_after==1);
+	assert(ret==IGRAPH_SUCCESS);
+	igraph_es_destroy(&es);
+
+	ret=igraph_es_pairs_small(&es, IGRAPH_DIRECTED, v[3], v[4], -1);
+	assert(ret==IGRAPH_SUCCESS);
+	edge_num_before=igraph_ecount(&g);
+	/* error test, no such edge to delete */
+	igraph_set_error_handler(igraph_error_handler_ignore);
+
+	ret=igraph_delete_edges(&g, es);
+	edge_num_after=igraph_ecount(&g);
+	assert(edge_num_before=edge_num_after);
+	assert(ret!=IGRAPH_SUCCESS);
+	igraph_es_destroy(&es);
+
+
+	igraph_destroy(&g);
+
+  return 0;
+}
+