Update documentation on .fromEnvironment. Make bool default be false.

runtime/lib/bool_patch.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.
 
 // Dart core library.
 
 patch class bool {
 
   /* patch */ const factory bool.fromEnvironment(String name,
-                                                 {bool defaultValue})
+                                                 {bool defaultValue = false})

[Søren Gjesse, 2013/10/31 08:14:30]

I guess this is OK, you can then use defautValue: null to check for "in
environment".

[Lasse Reichstein Nielsen, 2013/10/31 11:52:19]

You can, but you /should/ use the String constructor for that.

       native "Bool_fromEnvironment";
 
   int get _identityHashCode {
     return this ? 1231 : 1237;
   }
 }