SelectFeature control can now select across multiple vector

layers when passed an array of layers instead of a single layer with 
the constructor. This changeset also introduces a new layer type, 
Layer.Vector.RootContainer, which will be set as the topmost layer by 
the SelectFeature control and collect the svg/vml/canvas roots of 
multiple vector layers. r=crschmidt (closes #1666)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@9116 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

tests/Renderer/Elements.html

@@ -466,7 +466,7 @@
 
         OpenLayers.Util.getElement = OpenLayers.Util._getElement;
     }
-
+    
     function test_Elements_drawAndErase(t) {
         t.plan(20);
 
@@ -543,6 +543,19 @@
         tearDown();
     }
 
+    function test_Elements_moveRoot(t) {
+        t.plan(2);
+        setUp();
+        var r1 = create_renderer();
+        var r2 = create_renderer();
+        r1.moveRoot(r2);
+        t.xml_eq(r1.root.parentNode, r2.root.parentNode, "root moved successfully");
+        r1.moveRoot(r1);
+        t.xml_eq(r1.root.parentNode, r1.rendererRoot, "root moved back successfully");
+        tearDown();        
+    }
+
+
 
   </script>
 </head>