[IMP] components: add hooks mechanism

part of #194

src/index.ts

@@ -11,17 +11,21 @@ import { ConnectedComponent } from "./store/connected_component";
 import { Store } from "./store/store";
 import * as _utils from "./utils";
 import * as _tags from "./tags";
+import * as _hooks from "./hooks";
 import { Link } from "./router/Link";
 import { RouteComponent } from "./router/RouteComponent";
 import { Router } from "./router/Router";
 
 export { Component } from "./component/component";
 export { QWeb };
+
+export const useState = _hooks.useState;
 export const core = { EventBus, Observer };
 export const router = { Router, RouteComponent, Link };
 export const store = { Store, ConnectedComponent };
 export const utils = _utils;
 export const tags = _tags;
+export const hooks = _hooks;
 export const __info__ = {};
 
 Object.defineProperty(__info__, "mode", {