Move scanner out of generated and clean up imports

pkg/analyzer/lib/analyzer.dart

 // Copyright (c) 2013, 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 analyzer;
 
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/src/dart/scanner/reader.dart';
+import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/error.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/parser.dart';
-import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/string_source.dart';
 import 'package:path/path.dart' as pathos;
 
 export 'package:analyzer/dart/ast/ast.dart';
 export 'package:analyzer/dart/ast/visitor.dart';
 export 'package:analyzer/src/dart/ast/utilities.dart';
 export 'package:analyzer/src/error.dart';
 export 'package:analyzer/src/generated/error.dart';
 export 'package:analyzer/src/generated/utilities_dart.dart';
@@ skipping 97 matching lines @@
 
   /// The group of errors collected.
   AnalyzerErrorGroup get group =>
       new AnalyzerErrorGroup.fromAnalysisErrors(_errors);
 
   /// Whether any errors where collected.
   bool get hasErrors => !_errors.isEmpty;
 
   void onError(AnalysisError error) => _errors.add(error);
 }