outputs a new file called library_list.txt which will let the viewer know what libraries are availa…

pkg/docgen/lib/docgen.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.
 
 /**
  * **docgen** is a tool for creating machine readable representations of Dart 
  * code metadata, including: classes, members, comments and annotations.
  * 
  * docgen is run on a `.dart` file or a directory containing `.dart` files. 
  * 
@@ skipping 175 matching lines @@
             _getVariables(library.variables), _getMethods(library.functions),
             _getClasses(library.classes));
         if (outputToJson) {
           _writeToFile(stringify(result.toMap()), '${result.name}.json');
         } 
         if (outputToYaml) {
           _writeToFile(getYamlString(result.toMap()), '${result.name}.yaml');
         }
      }
     });
+    _writeToFile(listDir("docs").join('\n'), 'library_list.txt');
    }
 
   /// Saves list of libraries for Docgen object.
   void set libraries(value){
     _libraries = value;
   }
   
   /**
    * Returns any documentation comments associated with a mirror with
    * simple markdown converted to html.
@@ skipping 293 matching lines @@
   if (!dir.existsSync()) {
     dir.createSync();
   }
   File file = new File('docs/$filename');
   if (!file.existsSync()) {
     file.createSync();
   }
   file.openSync();
   file.writeAsString(text);
 }