Add changelog

Author: rtheunissen

CHANGELOG.md

@@ -0,0 +1,15 @@
+# Change Log
+All notable changes to this project will be documented in this file.
+This project adheres to [Semantic Versioning](http://semver.org/).
+
+## [1.1.0] - 2016-08-04
+### Added
+- `Pair::copy`
+
+## [1.0.3] - 2016-08-01
+### Added
+- `Set::merge`
+
+## [1.0.2] - 2016-07-31
+### Added
+- `Map::putAll`