Switch pkg packages, pub, and dartdoc to use package: imports.

pkg/fixnum/test/int_64_vm_test.dart

Index: pkg/fixnum/test/int_64_vm_test.dart
diff --git a/pkg/fixnum/test/int_64_vm_test.dart b/pkg/fixnum/test/int_64_vm_test.dart
index b9b4a9a97f004622791fdb41464412b3ef96ab95..b9d0f70f2775c561d3efcb10a2d6dbb406fd3c2c 100644
--- a/pkg/fixnum/test/int_64_vm_test.dart
+++ b/pkg/fixnum/test/int_64_vm_test.dart
@@ -5,11 +5,12 @@
 // A test to compare the results of the fixnum library with the Dart VM
 
 library int64vmtest;
+
 import 'dart:math' as math;
 
-part '../lib/src/int32.dart';
-part '../lib/src/int64.dart';
-part '../lib/src/intx.dart';
+part 'package:fixnum/src/int32.dart';
+part 'package:fixnum/src/int64.dart';
+part 'package:fixnum/src/intx.dart';
 
 final random = new math.Random();