Move core and coreimpl from corelib/ to lib/core and lib/coreimpl.

corelib/src/pattern.dart

Index: corelib/src/pattern.dart
diff --git a/corelib/src/pattern.dart b/corelib/src/pattern.dart
deleted file mode 100644
index 83a6765fcb024a5452d801c8747ebea042a2a617..0000000000000000000000000000000000000000
--- a/corelib/src/pattern.dart
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-interface Pattern {
-  Iterable<Match> allMatches(String str);
-}