Add logging system to pub and sprinkle some logging in.

utils/tests/pub/pub_test.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.
 
 library pub_tests;
 
 import 'dart:io';
 
 import 'test_pub.dart';
 import '../../../pkg/unittest/lib/unittest.dart';
 
 final USAGE_STRING = """
     Pub is a package manager for Dart.
 
     Usage: pub command [arguments]
 
     Global options:
-    -h, --help          Prints this usage information
-        --version       Prints the version of Pub
-        --[no-]trace    Prints a stack trace when an error occurs
+    -h, --help            print this usage information
+        --version         print the version of pub
+        --[no-]trace      print debugging information when an error occurs
+        --verbosity       control output verbosity
+
+              [all]       all output including internal tracing messages are shown
+              [io]        IO operations are also shown
+              [normal]    errors, warnings, and user messages are shown
+
+    -v, --verbose         shortcut for "--verbosity=all"
 
     Available commands:
       help      display help information for Pub
       install   install the current package's dependencies
       publish   publish the current package to pub.dartlang.org
       update    update the current package's dependencies to the latest versions
       version   print Pub version
 
     Use "pub help [command]" for more information about a command.
     """;
@@ skipping 49 matching lines @@
         error: '''
         Could not find a command named "quylthulg".
         Run "pub help" to see available commands.
         ''',
         exitCode: 64);
   });
 
   test('displays the current version', () =>
     runPub(args: ['version'], output: VERSION_STRING));
 }