S3 uploader grunt task
Required options:
files: expects an array of files
cdn: an object expecting 3 attributes
`bucket`: S3 bucket name
`key`: your S3 key
`secret`: your S3 secret
remotePath: any folder you want you file put in
useLocalFolderStructure: boolean, false means only the file is uploaded to the sha1 folder, true means that it mimics the local folder structure
baseDir: the base directory