When building directory indexes, we now add a`#md5=` to the end of the

filename in the link, indicating the MD5 checksum of the file, as

provided by S3.
This is used by pip (as part of the package-related PEPs) to verify the

authenticity of the files we provide. This, in theory, allows users to

install without using the --allow-unverified flag (though they still

need --allow-external, for now).
In practice, current versions of pip are still very hostile against

externally-hosted index.html files, which we use. This may be fixed in

pip 1.6, from the sounds of it. If so, we're now better set up for that.

Updated some test directories, and saw the proper md5sums. Downloaded and

verified they were correct.