Added Rx.Observable.of.
Added `exclusive` operator.
Added `exclusiveMap` operator.
`shareReplay` moved to `rx.binding-lite.d.ts`.
Removed `replayWhileObserved` from `rx.binding.d.ts` (replaced by `shareReplay`).
Added @since jsdoc attributes for new methods.
Added alias `just` for `return`.
Added `switchMap` alias for `selectSwitch`.
Version bump to 2.2.28
Merge pull request #2510 from Igorbek/RxJS-2.2.28

Update RxJS to version 2.2.28