* going from s3 to file target wasn't working
* use 'local' in the config instead of a file: url, for the local target, so it is not path-specific
* break out the S3 fields since users can't be expected to know how to form a URL
* use boto to generate a list of S3 hosts
* use boto to validate that the user input for s3 is valid
* fix lots of html errors in the backup admin