Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/operators/concatMapTo.js

@@ -0,0 +1,6 @@
+import { concatMap } from './concatMap';
+import { isFunction } from '../util/isFunction';
+export function concatMapTo(innerObservable, resultSelector) {
+    return isFunction(resultSelector) ? concatMap(function () { return innerObservable; }, resultSelector) : concatMap(function () { return innerObservable; });
+}
+//# sourceMappingURL=concatMapTo.js.map