docs(README): flip beta to release candidate

Author: benlesh

README.md

@@ -5,7 +5,7 @@
 
 [![Selenium Test Status](https://saucelabs.com/browser-matrix/rxjs5.svg)](https://saucelabs.com/u/rxjs5)
 
-# RxJS 5 (beta)
+# RxJS 5 (release candidate)
 
 Reactive Extensions Library for JavaScript. This is a rewrite of [Reactive-Extensions/RxJS](https://github.com/Reactive-Extensions/RxJS) and is intended to supersede it once this is ready. This rewrite is meant to have better performance, better modularity, better debuggable call stacks, while staying mostly backwards compatible, with some breaking changes that reduce the API surface.
 
@@ -106,7 +106,7 @@ npm install @reactivex/rxjs
 If you are using npm **version 2** before this library has achieved a stable version, you need to specify the library version explicitly:
 
 ```sh
-npm install @reactivex/[email protected]beta.1
+npm install @reactivex/[email protected]rc.1
 ```
 
 ### CDN