Added uploaded_file instance variable for new assigns
Tracking new attachment styles with a Rake task to refresh them
Adding tests and logic to ensure that tempfiles are closed and unlinked after queued_for_writes finishes uploading/saving
Ensure filename is not nil before cheking file existance
Updated README with instructions for using missing_styles task
Merge remote branch 'upstream/master'

Conflicts:
	README.md
More readable doc
Remove the restriction on Processor ancestry.
Add a Paperclip.register_processor configuration.
Merge branch 'features/tempfile_cleanup' of https://github.com/danielevans/paperclip
Merge branch 'master' of https://github.com/murbanski/paperclip
Bump to 2.4.0
Fix whitespacing issue
Default the style to default style in #s3_protocol method of S3 storage

Thank you @eric-hu for reporting this regression.

Closes #583
Set the logger to be `AR::Base.logger` or `Rails.logger` when the gem is included to Rails

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
Also set the log of the test suite to a file as it used to be
Upgrade Rails versions to test against
Remove the Gemfile.lock from git cache

We've ignored the lock file at 3f56e7038e8295e8a8793d605d7c377a7e95a4cf, so we should remove it as well.
Update version in README to 2.4
Remove duplicate test case