A little wrapper for uploading files to s3 via a MultipartReader stream.
Usage example:
var r = http.Request newFilename, originalFilename, fileExtension, mimeType, err := s3Uploader.Upload(r, s3Uploader.AwsSettings{ AccessKey: "s3-access-key", SecretKey: "s3-secret-key", Bucket: "s3-bucket", })