Rename DownloadResolverRegistry to DownloadResolverManager

- And delete DownloadResolverFactory
Rename DownloadResolver.getUnpackedDirectorName

- Fix spelling to getUnpackedDirectoryName
Rename EntityDownloadManager.resolve(...) to newDownloader(...)
Merge pull request #601 from ahgittin/misc

entity short names, and jclouds uses entity info (e.g. short names if available) when creating machines
Merge pull request #584 from aledsage/fix/api-DownloadResolverManager

api download resolver manager