Re #149: Spawn background process to save new attachments to S3.
Re #149: Show status message in place of thumbnail while uploading file to S3.
Re #149: Only show "Thumbnail generating" when a file has been uploaded.
Re #149: Retry 5 times failed S3 uploads.
Remove unnecessary S3 retry logic.
Name DJ export queue.
Re #149: Handle async S3 attachment transfer with DJ.
EY deploy hook to create shared tmp/files directory.
Fix file upload check error.
Handle various forms of content_type
Move file attribute extraction out of controller.
Store tempfile name, not path.
Update script/rails to be Ruby-version-agnostic.
Update boot file for Rails 3.0.20
Re #149: Generate thumbnails in the DJ background job.
Re #149: Allow submission of contributions with thumbnails pending generation.