Added new deploy option for Amazon S3 that uses aws-sdk instead of pkgcloud

Since pkgcloud seems to have some issues with S3 (see #66) this alternative uses aws-sdk.
This method also only uploads changed files to S3 and has a verbose option.
You can also pass the gzip option to StaticAssets with this method, and it will compress *.js, *.css, *.txt, *.html and *.xml files.