(cherry picked from commit 67865aac3227bd9c515052f6fbee446b4e724971)

(cherry picked from commit e053805f55b872e6926dfbfa14f38d1296e8b922)

Based on a commit by Henrik N <henrik@nyh.se>

Oops, I forgot to regenerate the gemspec
Railtie_name was deprecared in Rails edge - See 395d664

(cherry picked from commit 4418c7a7229bd683b8f7597a2ab72149460608ab)

Moved AR include into a configure method to prevent non-inclusion when using the git repo in the Gemfile

Rails.root returns a Pathname and you can now declare your attachment
without having to call #to_s first:

has_attached_file :avatar,
                  :storage => :s3,
                  :s3_credentials => Rails.root.join('s3.yml')
(cherry picked from commit 65d7600b7246cb3bd8f10805fb618e5839694318)

Added a rake task for testing all versions. Changed gem statements to use ~> instead of hard versions.

These callbacks are different from pre-rails 3. They do NOT cancel the
after_ if the before_ returns false. They will cancell inner callbacks,
however, but that's it. This is a change in functionality.