Finally remove `:disable_with` but use `:data => { :disable_with => ... }`
in examples to show off a better API (which looks nicer in Ruby 1.9)
This reverts commit a5c38a9c08.
`disable_with:` is much easier to type than `"data-disable-with" =>`,
and the fact it uses "data-disable-with" => is an implementation concern,
it should not affect the public API.
This reverts commit 683fc4db00.