docs(changelog): add changelog for 2.4.0

Author: chuckjaz

CHANGELOG.md

@@ -1,3 +1,23 @@
+<a name="2.4.0"></a>
+# [2.4.0 stability-interjection](https://github.com/angular/angular/compare/2.3.1...2.4.0) (2016-12-20)
+
+
+### Bug Fixes
+
+* **animations:** allow players to be destroyed before initialized ([#13346](https://github.com/angular/angular/issues/13346)) ([b36f4bc](https://github.com/angular/angular/commit/b36f4bc)), closes [#13293](https://github.com/angular/angular/issues/13293)
+* **build:** use bash string comparison operator ([#13502](https://github.com/angular/angular/issues/13502)) ([50afbe0](https://github.com/angular/angular/commit/50afbe0))
+* **compiler:** do not lex `}}` when interpolation is disabled ([#13531](https://github.com/angular/angular/issues/13531)) ([9b87bb6](https://github.com/angular/angular/commit/9b87bb6)), closes [#13525](https://github.com/angular/angular/issues/13525)
+* **compiler-cli:** produce metadata for .d.ts files without metadata ([#13526](https://github.com/angular/angular/issues/13526)) ([debb0c9](https://github.com/angular/angular/commit/debb0c9)), closes [#13307](https://github.com/angular/angular/issues/13307) [#13473](https://github.com/angular/angular/issues/13473) [#13521](https://github.com/angular/angular/issues/13521)
+* **i18n:** add a default example to xmb placeholders ([#13507](https://github.com/angular/angular/issues/13507)) ([3f17841](https://github.com/angular/angular/commit/3f17841))
+* **upgrade:** fix `registerForNg1Tests` ([#13522](https://github.com/angular/angular/issues/13522)) ([c26c24c](https://github.com/angular/angular/commit/c26c24c))
+
+
+### Features
+
+* update to `rxjs@5.0.1` and unpin the rxjs peerDeps via `^5.0.1` ([#13572](https://github.com/angular/angular/issues/13572)) ([8d5da1e](https://github.com/angular/angular/commit/8d5da1e)), closes [#13561](https://github.com/angular/angular/issues/13561) [#13478](https://github.com/angular/angular/issues/13478)
+
+
+
 <a name="2.3.1"></a>
 ## [2.3.1](https://github.com/angular/angular/compare/2.3.0...2.3.1) (2016-12-15)