Let the possibility to delete specific iteration of a package

e.g.:

deb-s3 delete --versions packageA-42
Fix `verify` and `delete`.
Introduce in 3e347127e99904e8fb279805798744fa36586275
Merge pull request #56 from guilhem/fix_Release.retrieve

Fix `verify` and `delete`.
Merge pull request #48 from remh/patch-1

Let the possibility to delete specific iteration of a package
Added command to copy package entry between manifests.
Added a list command to list out one component of a codename
Added 'show' command to show package details in manifest.

Also a 'quiet' flag so that show can be used to check existence by
return code.
Update aws-sdk gem

Pin nokogiri to 1.5.x as 1.6 doesn't support Ruby 1.8.7.
Modified control parser so extra fields are kept
Added '--long' option to list command

To show all fields in original format.