More properly coded version for adding edges... now only do_versions()

reads from the old mface->edcode flag to set edge drawing.

ALso; added a pointer check in draw_mesh_object(), here the derivedmesh
gives NULL on reading regression file lostride.blend. Zr needs to check!

source/blender/python/api2_2x/NMesh.c

@@ -2818,7 +2818,7 @@ static void fill_medge_from_nmesh(Mesh * mesh, BPy_NMesh * nmesh)
   valid_nmedges=MEM_callocN(nmeshtotedges*sizeof(BPy_NMEdge *), "make BPy_NMEdge");
 
   /* First compute the list of edges that exists because faces exists */
-  make_edges(mesh);
+  make_edges(mesh, 0);	/* 0 = draw all edges */
 
   faces_edges=mesh->medge;
   tot_faces_edges=mesh->totedge;