Add web front-end and fix API issues

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

@@ -0,0 +1,12 @@
+import { createErrorClass } from './createErrorClass';
+export var UnsubscriptionError = createErrorClass(function (_super) {
+    return function UnsubscriptionErrorImpl(errors) {
+        _super(this);
+        this.message = errors
+            ? errors.length + " errors occurred during unsubscription:\n" + errors.map(function (err, i) { return i + 1 + ") " + err.toString(); }).join('\n  ')
+            : '';
+        this.name = 'UnsubscriptionError';
+        this.errors = errors;
+    };
+});
+//# sourceMappingURL=UnsubscriptionError.js.map