use suro file's lastModify/dateCreated time for build upload path

#140 

configuration:
        "prefixFormatter":{
            "type":"FileDate",
            "format":"yyyy/MM/dd/HH",
            "dateType":"lastModify or dateCreated" //default dateCreated
        },
Why is P20141006T213521 hardcoded? This might need more explanation or comments.