Added a chapter about the navigation on a mesh.

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@231 fdac6126-5c0c-442c-9429-916003d36597

Doc/Examples/nav_code1.cc

@@ -0,0 +1,19 @@
+[...]
+
+TriMesh::HalfedgeHandle heh, heh_init;
+
+// Get the halfedge handle assigned to vertex[0]
+heh = heh_init = mesh.halfedge_handle(vertex[0].handle());
+
+// heh now holds the handle to the initial halfedge.
+// We now get further on the boundary by requesting
+// the next halfedge adjacent to the vertex heh
+// points to...
+heh = mesh.next_halfedge_handle(heh);
+
+// We can do this as often as we want:
+while(heh != heh_init) {
+	heh = mesh.next_halfedge_handle(heh);
+}
+
+[...]