RxJS RC0 removed the cache operator - see ReactiveX/rxjs#2012 for more detail
This gist includes the removed operator in case you are using it in existing app. We recommend migrating off of this operator in favor of a supported one, but you may use this one temporarily.
If you're using Typescript, simply include the .ts file in the gist somewhere in your project, and import the file somewhere in your app.
If you're using an ES5 build of Angular, simply require or include the cache-operator.umd.js file included here.