Added missing target param on s3.get_object

This adds info about the target parameter as per:

http://ruby.awsblog.com/post/Tx354Y6VTZ421PJ/Downloading-Objects-from-Amazon-S3-using-the-AWS-SDK-for-Ruby

I've also added a .gitignore entry for Vim's .swp files. Yes, we do use Vim for documentation. ;)