Update changelog

Author: rtheunissen

CHANGELOG.md

@@ -2,6 +2,13 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [1.1.1] - 2016-08-09
+### Fixed
+- `Stack` and `Queue` array access should throw `OutOfBoundsException`, not `Error`.
+
+### Improved
+- Added a lot of docblock comments that were missing.
+
 ## [1.1.0] - 2016-08-04
 ### Added
 - `Pair::copy`