docs: improve the GitHub README.md, update links, etc

Author: IgorMinar

README.md

@@ -5,10 +5,6 @@
 [![npm version](https://badge.fury.io/js/%40angular%2Fcore.svg)](https://www.npmjs.com/@angular/core)
 
 
-[![Sauce Test Status](https://saucelabs.com/browser-matrix/angular2-ci.svg)](https://saucelabs.com/u/angular2-ci)
-
-*Safari (7+), iOS (7+) and IE mobile (11) are tested on [BrowserStack][browserstack].*
-
 # Angular
 
 Angular is a development platform for building mobile and desktop web applications using Typescript/JavaScript and other languages.
@@ -17,12 +13,19 @@ Angular is a development platform for building mobile and desktop web applicatio
 
 [Get started in 5 minutes][quickstart].
 
+
+## Changelog
+
+[Learn about the latest improvements][changelog]. 
+
+
 ## Want to help?
 
 Want to file a bug, contribute some code, or improve documentation? Excellent! Read up on our
 guidelines for [contributing][contributing] and then check out one of our issues in the [hotlist: community-help](https://github.com/angular/angular/labels/hotlist%3A%20community-help).
 
 [browserstack]: https://www.browserstack.com/automate/public-build/LzF3RzBVVGt6VWE2S0hHaC9uYllOZz09LS1BVjNTclBKV0x4eVRlcjA4QVY1M0N3PT0=--eb4ce8c8dc2c1c5b2b5352d473ee12a73ac20e06
-[contributing]: http://github.com/angular/angular/blob/master/CONTRIBUTING.md
-[quickstart]: https://angular.io/docs/ts/latest/quickstart.html
-[ng]: http://angular.io
+[contributing]: https://github.com/angular/angular/blob/master/CONTRIBUTING.md
+[quickstart]: https://angular.io/guide/quickstart
+[changelog]: https://github.com/angular/angular/blob/master/CHANGELOG.md
+[ng]: https://angular.io