Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/util/isInteropObservable.js

@@ -0,0 +1,6 @@
+import { observable as Symbol_observable } from '../symbol/observable';
+import { isFunction } from './isFunction';
+export function isInteropObservable(input) {
+    return isFunction(input[Symbol_observable]);
+}
+//# sourceMappingURL=isInteropObservable.js.map