Added changelog file

CHANGELOG.md

@@ -0,0 +1,19 @@
+# Changelog
+
+#### n2n 2.4 (August 2018)
+
+This is the first release after 2012 and thus it is focusing mainly
+on making it work on current operating system versions, so that the
+next release will be based on modern code
+
+## New features
+* Added deb/rpm packages
+* Added systemd configuration files
+* Added ability to read configuration files instead of using only the CLI (needed for packaging)
+* Added n2n Android app
+* Implemented simple API to embed n2n in applications (in addition to use it stand-alone)
+
+## Improvements
+* Major code cleanup
+* Fixed compilation issues on MacOS
+* Fixed Linux segmentation fault