Move all flags to CompilerOptions (first step to stop passing the compiler to

pkg/dart2js_incremental/lib/dart2js_incremental.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_incremental;
 
 import 'dart:async' show
     EventSink,
     Future;
 
 import 'dart:developer' show
     UserTag;
 
 import 'package:compiler/src/apiimpl.dart' show
     CompilerImpl;
 
 import 'package:compiler/compiler_new.dart' show
     CompilerDiagnostics,
     CompilerInput,
     CompilerOutput,
+    CompilerOptions,
     Diagnostic;
 
 import 'package:compiler/src/null_compiler_output.dart' show
     NullCompilerOutput;
 
 import 'package:compiler/src/js_backend/js_backend.dart' show
     JavaScriptBackend;
 
 import 'package:compiler/src/js_emitter/full_emitter/emitter.dart'
     as full show Emitter;
@@ skipping 130 matching lines @@
   }
 }
 
 class IncrementalCompilationFailed {
   final String reason;
 
   const IncrementalCompilationFailed(this.reason);
 
   String toString() => "Can't incrementally compile program.\n\n$reason";
 }