Moved most of html lib generating scripts into tools.

tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate

 // 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.
 
 
 /// @domName KeyboardEvent; @docsEditable true
 class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   factory $CLASSNAME(String type, Window view,
       [bool canBubble = true, bool cancelable = true,
@@ skipping 26 matching lines @@
     }
   }
 
   /** @domName KeyboardEvent.keyCode */
   int get keyCode => $dom_keyCode;
 
   /** @domName KeyboardEvent.charCode */
   int get charCode => $dom_charCode;
 $!MEMBERS
 }