pkg/utf: fixed layout, added todos, updated docs and homepage pubspec links

pkg/utf/lib/constants.dart

Index: pkg/utf/lib/constants.dart
diff --git a/pkg/utf/lib/constants.dart b/pkg/utf/lib/constants.dart
deleted file mode 100644
index 11d0cc2b2457b9203b583560da57b80cf0896de0..0000000000000000000000000000000000000000
--- a/pkg/utf/lib/constants.dart
+++ /dev/null
@@ -1,25 +0,0 @@
-// 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.
-
-part of utf;
-
-/**
- * Invalid codepoints or encodings may be substituted with the value U+fffd.
- */
-const int UNICODE_REPLACEMENT_CHARACTER_CODEPOINT = 0xfffd;
-const int UNICODE_BOM = 0xfeff;
-const int UNICODE_UTF_BOM_LO = 0xff;
-const int UNICODE_UTF_BOM_HI = 0xfe;
-
-const int UNICODE_BYTE_ZERO_MASK = 0xff;
-const int UNICODE_BYTE_ONE_MASK = 0xff00;
-const int UNICODE_VALID_RANGE_MAX = 0x10ffff;
-const int UNICODE_PLANE_ONE_MAX = 0xffff;
-const int UNICODE_UTF16_RESERVED_LO = 0xd800;
-const int UNICODE_UTF16_RESERVED_HI = 0xdfff;
-const int UNICODE_UTF16_OFFSET = 0x10000;
-const int UNICODE_UTF16_SURROGATE_UNIT_0_BASE = 0xd800;
-const int UNICODE_UTF16_SURROGATE_UNIT_1_BASE = 0xdc00;
-const int UNICODE_UTF16_HI_MASK = 0xffc00;
-const int UNICODE_UTF16_LO_MASK = 0x3ff;