Broken links in examples/README.md

[YukihiroArakawa]

I found broken links in examples/README.md.

Here:

• Booking
• Chat
• Validation
• Upload
• Twitter OAuth
• Facebook OAuth2

[YukihiroArakawa]

I think following links are correct:

* [Booking](https://revel.github.io/examples/booking.html)
  - A database-driven hotel-booking application, including user management

* [Chat](https://revel.github.io/examples/chat.html)
  - A chat room demonstrating active refresh, long-polling (comet), and [websocket](http://revel.github.io/manual/websockets.html) implementations.

* [Validation](https://revel.github.io/examples/validation.html)
  - A demonstration of input [validation](http://revel.github.io/manual/validation.html).

* [Upload](https://revel.github.io/examples/upload.html)
  - Demonstrates single and multiple file uploads to a webserver via http.

* [Twitter OAuth](https://revel.github.io/examples/twitter-oauth.html)
  - Display `mentions` and allows `posting` to a Twitter account using OAuth.

* [Facebook OAuth2](https://revel.github.io/examples/facebook-oauth2.html)
  - Display Facebook user information using OAuth2.

[notzippy]

Thankyou, updated readme accordingly