Merge pull request #1937 from david-driscoll/fix-promise-input

style(typings): updated ObservableInput<T> to use PromiseLike<T> instead of Promise<T>

src/Observable.ts

@@ -14,7 +14,7 @@ export interface Subscribable<T> {
             complete?: () => void): AnonymousSubscription;
 }
 
-export type SubscribableOrPromise<T> = Subscribable<T> | Promise<T>;
+export type SubscribableOrPromise<T> = Subscribable<T> | PromiseLike<T>;
 export type ObservableInput<T> = SubscribableOrPromise<T> | ArrayLike<T>;
 
 /**