Rename rendering/render_*.dart to rendering/*.dart

sky/sdk/lib/framework/rendering/flex.dart

Index: sky/sdk/lib/framework/rendering/flex.dart
diff --git a/sky/sdk/lib/framework/rendering/render_flex.dart b/sky/sdk/lib/framework/rendering/flex.dart
similarity index 98%
rename from sky/sdk/lib/framework/rendering/render_flex.dart
rename to sky/sdk/lib/framework/rendering/flex.dart
index 5ef24fdf987a2c0cc96f526b695bff98ecf7be20..385c0cb7e4301ee8df4dc5bd629185f182e7cc6a 100644
--- a/sky/sdk/lib/framework/rendering/render_flex.dart
+++ b/sky/sdk/lib/framework/rendering/flex.dart
@@ -3,8 +3,8 @@
 // found in the LICENSE file.
 
 import 'dart:sky' as sky;
-import 'render_box.dart';
-import 'render_node.dart';
+import 'box.dart';
+import 'node.dart';
 
 class FlexBoxParentData extends BoxParentData with ContainerParentDataMixin<RenderBox> {
   int flex;