Roll Observatory packages and add a roll script

packages/quiver/CHANGELOG.md

+#### 0.21.4 - 2015-05-15
+   * Add stats reporting for fake async tests. You can query the number of 
+     pending microtasks and timers via `microtaskCount`, `periodicTimerCount`, 
+     `nonPeriodicTimerCount`.
+                                         
+#### 0.21.3+1 - 2015-05-11
+   * Switch from unittest to test.
+
+#### 0.21.3 - 2015-03-03
+   * Bugfix: fixed return type on some methods (e.g. `where` of `Iterable`s
+     returned by Multimap.
+
+#### 0.21.2 - 2015-03-03
+   * Bugfix: fix drifting times in `Metronome`.
+   * Add `LruMap` to quiver/collection.
+   * Un-deprecate Glob; feedback was that package:glob was not a suitable
+     replacement in many cases. Key reasons: dependency on dart:io and
+     significantly poorer performance.
+
+#### 0.21.1 - 2015-02-05
+   * Add optional start param to `Glob.allMatches()` to match superclass
+     method signature.
+   * Add optional start param to `Pattern` returned by `matchesAny()` to match
+     superclass method signature.
+   * Deprecate Glob. Use package:glob. Will be removed in 0.22.0.
+
+#### 0.21.0+3 - 2015-02-04
+   * Travis CI integration support added.
+   * Document that the deprecated functions `padLeft`, `padRight`, `trimLeft`,
+     `trimRight` will be removed in 0.22.0.
+
+#### 0.21.0+2 - 2015-02-04
+   * Fix hanging `FakeAsync` unit test.
+
+#### 0.21.0+1 - 2015-02-03
+   * Replace `equalsTester` dependency on `unittest` with finer-grained
+     dependency on `matcher`.
+   * `path` is now a dev dependency.
+
+#### 0.21.0 - 2015-02-02
+   * Multimap: `toMap()` is deprecated and replaced with `asMap()`. `toMap()`
+     will be removed in v0.22.0.
+   * Cleanup method signatures that were inconsistent with the core library.
+   * Added `areEqualityGroups` matcher for testing `operator==` and `hashCode`.
+   * CONTRIBUTING.md added.
+
+#### 0.20.0 - 2014-12-10
+   * Multimap: better `toString()` on returned collections.
+   * Multimap: Bugfix: support edits on empty value collections.
+   * Multimap: Added missing return statment in `fold`.
+   * Added isEmpty() in `strings`.
+   * Added max SDK constraint <2.0.0
+   * Minor updates to README.md.
+   * CHANGELOG.md added
+
+#### 0.19.0+1 - 2014-11-12
+   * Corrected version constraint suggestion in README.md.