* Update README * Add docs for fromObservable * Add docs for fromCallbag * Add docs for toCallbag and toObservable * Add docs for buffer * Add docs for concatAll * Add docs for mergeAll and mergeMap * Add docs for share * Add docs for switchMap and switchAll * Fix filename of interval source * Add docs for interval * Reformat code snippets in operators doc * Add docs for debounce and throttle * Move sample operator out of web The sample operator doesn't use Web-specific APIs and can hence be moved to be a generic operator. * Add docs for sample * Add notes on interoperability to Getting Started