todo

P1
* all the readXXX() shoud check if this.data is already set.
* separate readXXX, writeXXX registration
* 
* Code coverage
* Form Handling

* Upload files
  * Duplicate file upload
  * Large file upload
    * when restricted at route level
  
* writeFile
    automatically detect file's content/mime type

P2

* Form Handling
    parse : true; //parse numeric, boolean fields
    acceptUnknown : true
    acceptUnknown : false
        fields : [ ]
        onUnknownField

    file :
        counter : 0 // -1, 3
        onExceed : 
            error when counter increases
            delete temp files
  * readFiles
* google protobuf
* msgpack
* Nimn
* emit event
* pass mime type(s) in readXXX() to verify header before reading


P3
* Calling validater 
* readFile
* readForm
* readFormFields
* readFiles


multiples : true
{
  "files": {
    "upload": [ // it'll not be an array if multiples: false
      {
        "size": 748831,
        "path": "/tmp/f7777b4269bf6e64518f96248537c0ab.png",
        "name": "balo3.png",
        "type": "image/png",
        "mtime": "2014-06-17T11:08:52.816Z"
      },
      {
        "size": 379749,
        "path": "/tmp/83b8cf0524529482d2f8b5d0852f49bf.jpeg",
        "name": "phpcode.jpeg",
        "type": "image/jpeg",
        "mtime": "2014-06-17T11:08:52.830Z"
      }
    ]
  },
  "fields": {
    "title": ""
  }
}