This will make sure Interpolations is comply with Ruby's Object#hash

Closes #569, Closes #603

This test will generate a basic Rails application, include Paperclip
into Gemfile, and call basic `has_attached_file` in the model. This will
make sure that we're not messing up any of the configuration and
integration for our gem and the Rails framework.

Thanks @GMFlash!

Closes #586

Thank you @excid3 for suggestion.

Closes #582

We've ignored the lock file at 3f56e703, so we should remove it as well.

However, this will make sure that you can always change it to something else afterward.

There's currently no test for this, but after I've tried this with the `integration_test` branch, I can confirm that logs are written to `log/test.log` as it should.

Closes #581

Thank you @eric-hu for reporting this regression.

Closes #583

Conflicts:
	README.md

Fixing destroy callback to delete files just when model destroy method was completed successfully (i.e. no exception like 'foreign key constraint violations' was raised)

Adding tests and logic to ensure that tempfiles are closed and unlinked after queued_for_writes finishes uploading/saving

When testing if post_processing is set, the method should be used. This allows plugins to overwrite the post_processing decision. This is useful for plugins that want to do the post_processing in a background processor.

An implemenation of the watermark processor alluded to is in this gist
https://gist.github.com/1171081

Decouple the Interpolations class from the Attachment classs, you can extend Paperclip with custom interpolations as paperclip-extended does.

Abstract out the file geometry parser within Thumbnail. This makes it possible to have different cropping and scaling controls, as the papermill gem does.