Create associated packages for the dart:collection and dart:async libs.

pkg/collection_helpers/README.md

-Helper libraries for working with collections.
+Deprecated helper libraries for working with collections.
 
-The `collection_helpers` package contains a number of separate libraries
-with utility functions and classes that makes working with collections easier.
+The `collection_helpers` package has been split into the
+`collection` package (for most of the library)
+and the `typed_data` package (for typed data buffers).
 
-## Using
+All further development will happen on those libraries.
 
-The `collection_helpers` library can be imported as separate libraries, or
-in totality:
-
-    import 'package:collection_helpers/equality.dart';
-    import 'package:collection_helpers/algorithms.dart';
-    import 'package:collection_helpers/wrappers.dart';
-
-or
-
-    import 'package:collection_helpers/all.dart';
-
-## Equality
-
-The equality library gives a way to specify equality of elements and
-collections.
-
-Collections in Dart have no inherent equality. Two sets are not equal, even
-if they contain exactly the same objects as elements.
-
-The equality library provides a way to say define such an equality. In this
-case, for example, `const SetEquality(const IdentityEquality())` is an equality
-that considers two sets equal exactly if they contain identical elements.
-
-The library provides ways to define equalities on `Iterable`s, `List`s, `Set`s, and
-`Map`s, as well as combinations of these, such as:
-
-    const MapEquality(const IdentityEquality(), const ListEquality());
-
-This equality considers maps equal if they have identical keys, and the corresponding values are lists with equal (`operator==`) values.
-
-## Algorithms
-
-The algorithms library contains functions that operate on lists.
-
-It contains ways to shuffle a `List`, do binary search on a sorted `List`, and
-some different sorting algorithms.
-
-
-## Wrappers
-
-The wrappers library contains classes that "wrap" a collection.
-
-A wrapper class contains an object of the same type, and it forwards all
-methods to the wrapped object.
-
-Wrapper classes can be used in various ways, for example to restrict the type
-of an object to that of a supertype, or to change the behavior of selected
-functions on an existing object.
+Please start using those libraries directly.