Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/fetch/index.js

@@ -0,0 +1,2 @@
+export { fromFetch } from '../internal/observable/dom/fetch';
+//# sourceMappingURL=index.js.map

node_modules/rxjs/dist/esm5/fetch/index.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../../../src/fetch/index.ts"],"names":[],"mappings":"AAAA,OAAO,EAAE,SAAS,EAAE,MAAM,kCAAkC,CAAC"}