Add note about changes to send/respond_to? in Ruby 2.0

```
Should add a note about how send/respond_to? will respect protected methods in 
Ruby 2.0.

http://tenderlovemaking.com/2012/09/07/protected-methods-and-ruby-2-0.html
```

Original issue reported on code.google.com by `postmode...@gmail.com` on 21 Sep 2012 at 2:07
