Add CHANGELOG

Source:
https://github.com/reactphp/react/blob/a6de34d61f68adebd3cc3b855268a5f1475749b8/CHANGELOG.md

Author: clue

CHANGELOG.md

@@ -0,0 +1,49 @@
+# Changelog
+
+## 0.4.1 (2014-04-13)
+
+* Bug fix: Fixed PSR-4 autoload path (@marcj/WyriHaximus)
+
+## 0.4.0 (2014-02-02)
+
+* BC break: Bump minimum PHP version to PHP 5.4, remove 5.3 specific hacks
+* BC break: Update to React/Promise 2.0
+* Bug fix: Properly resolve CNAME aliases
+* Dependency: Autoloading and filesystem structure now PSR-4 instead of PSR-0
+
+## 0.3.2 (2013-05-10)
+
+* Feature: Support default port for IPv6 addresses (@clue)
+
+## 0.3.0 (2013-04-14)
+
+??
+
+## 0.2.6 (2012-12-26)
+
+* Feature: New cache component, used by DNS
+
+## 0.2.5 (2012-11-26)
+
+??
+
+# 0.2.4 (2012-11-18)
+
+* Feature: Change to promise-based API (@jsor)
+
+## 0.2.3 (2012-11-14)
+
+??
+
+## 0.2.2 (2012-10-28)
+
+* Feature: DNS executor timeout handling (@arnaud-lb)
+* Feature: DNS retry executor (@arnaud-lb)
+
+## 0.2.1 (2012-10-14)
+
+* Minor adjustments to DNS parser
+
+## 0.2.0 (2012-09-10)
+
+* Feature: DNS resolver