Cleanup 1: split parts into their own libraries, remove unused imports

pkg/compiler/lib/src/js_emitter/model.dart

 // Copyright (c) 2014, 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 dart2js.new_js_emitter.model;
 
-import '../common.dart';
 import '../constants/values.dart' show
     ConstantValue;
 import '../deferred_load.dart' show
     OutputUnit;
 import '../elements/elements.dart' show
     Element;
 import '../js/js.dart' as js show
     Expression,
     Literal,
     Name,
@@ skipping 512 matching lines @@
               functionType: functionType);
 
   bool get isStatic => true;
 }
 
 class StaticStubMethod extends StubMethod implements StaticMethod {
   Holder holder;
   StaticStubMethod(js.Name name, this.holder, js.Expression code)
       : super(name, code);
 }