Add priority queue to package:collection.

pkg/collection/README.md

Index: pkg/collection/README.md
diff --git a/pkg/collection/README.md b/pkg/collection/README.md
index bb392fd385d420ee42f4f7656ecc0707c4cd1fa5..7ebd62af2d318d0c8001c9b3d70a429434d62b9f 100644
--- a/pkg/collection/README.md
+++ b/pkg/collection/README.md
@@ -8,14 +8,24 @@ with utility functions and classes that makes working with collections easier.
 The `collection` package can be imported as separate libraries, or
 in totality:
 
-    import 'package:collection/equality.dart';
     import 'package:collection/algorithms.dart';
+    import 'package:collection/equality.dart';
+    import 'package:collection/iterable_zip.dart';
+    import 'package:collection/priority_queue.dart';
     import 'package:collection/wrappers.dart';
 
 or
 
     import 'package:collection/collection.dart';
 
+## 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
+various sorting algorithms.
+
+
 ## Equality
 
 The equality library gives a way to specify equality of elements and
@@ -28,19 +38,23 @@ 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:
+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.
+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.
+## Iterable Zip
 
-It contains ways to shuffle a `List`, do binary search on a sorted `List`, and
-some different sorting algorithms.
+Utilities for "zipping" a list of iterables into an iterable of lists.
+
+
+## Priority Queue
+
+An interface and implemention of a priority queue.
 
 
 ## Wrappers