Rename KindleForMac Cask class to Kindle
user
```ruby
class Kindle < Cask
  url 'http://kindleformac.amazon.com/40499/KindleForMac.dmg'
  homepage 'http://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000464931'
  version '1.10.6 (40499)'
  sha1 'a086df6a67e97460fb09b6d115f71d952487ac38'
  link 'Kindle.app'
end
```
assistant