S3Csv Fdw

I wrote an Amazon S3 fdw that is based on the CSV fdw. It uses the boto library to get the file from amazon. I was able to verify this worked on Ubuntu, but my local homebrew python installation does not work - it blows up on some python devel header that is missing.

If anybody gives it a spin, make sure to use it only with lowercase bucket names - that is what boto expects. Huge thanks for an amazing job with this library -- I was pulling my hair out trying to get an old c-based postgres 9.1 s3fwd to work but couldn't figure it out so multicorn saved my day!