Deprecate Math object in corelib in favor of dart:math library.

samples/swipe/swipe.dart

 // Copyright (c) 2012, 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.
 
 #library("swipe");
 
 #import('dart:html');
+#import('dart:math', prefix: 'Math');
 
 Element target;
 
 var figureWidth;
 
 double anglePos = 0.0;
 
 var timeoutHandle;
 
 void main() {
@@ skipping 100 matching lines @@
 
 /**
  * Stop any spin that may be in progress.
  */
 void stopSpin() {
   if (timeoutHandle != null) {
     window.clearInterval(timeoutHandle);
     timeoutHandle = null;
   }
 }