list s3 buckets using the aws sdk

s3_list.swift

AWSS3.defaultS3().listBuckets(nil).continueWithBlock {
    (task: BFTask!) -> AnyObject! in
    let output : AWSS3ListBucketsOutput = task.result() as AWSS3ListBucketsOutput
    println("found \(output.buckets.count) buckets")
    
    for bucket in output.buckets as [AWSS3Bucket] {
        println("Found bucket \(bucket.name)")
    }
    
    return nil
}